Determining the sex of a child by ultrasound is not included in the fetometry (measurement) of the fetus. To find out who will be there, there is a separate procedure in private medical centers. The cost of the service starts from 500 rubles. You can pay extra for it when ordering routine ultrasound screening. State antenatal clinics provide examinations free of charge at the place of registration. At the request of the pregnant woman, the expected gender will be revealed during the second ultrasound.
How is the gender of the fetus formed?
In the early stages of pregnancy, the phenotype of the embryos is identical, that is, for several weeks after conception, gender formation does not occur. Differentiation is based on a sequence of specific events that occur due to chromosome composition.
In humans, as in other mammals, sex is determined by the type of chromosome carried by the sperm that fertilizes the egg. The key concept is the carotype; if it contains the Y chromosome, then the fetus will be male, and if it is absent, it will be female.
The human gonads are formed from the gonad, which during development becomes either a testis or an ovary. Thus, the karotype forms the direction of development of the gonad, and the gonads stimulate the formation of internal and external organs.
What determines the accuracy of sex determination?
For up to 12 weeks, the external genitalia of males and females have a similar structure, which makes their diagnosis most difficult.
Most often, one of the reasons why it is impossible to diagnose the sex of the fetus is its inconvenient position for examination. The baby may squeeze or cross his legs, press them to his stomach - all this prevents the doctor from examining and assessing the fetal perineal area.
In some situations, umbilical cord loops, fingers or swollen labia can imitate the image of the penis and scrotum.
In addition, an unclear image during transabdominal access due to the constitutional characteristics of a pregnant woman, in particular thick subcutaneous fat on the abdomen, may prevent reliable determination of the sex of the child. The reliability of sex determination is also affected by the amount of amniotic fluid: if there is very little of it, then it is difficult for the doctor to examine the small details of the baby’s body.
At what month of pregnancy are sexual characteristics formed?
The formation of the fetus is a long, step-by-step process.
The reproductive system begins to form in the sixth week, but up to the ninth we are talking about internal organs that are absolutely identical in boys and girls. Even experienced specialists and high-quality equipment cannot determine the baby’s gender. By the twelfth week, the first signs of difference begin to appear:
- in boys – formation of the penis;
- in girls - labia.
If the child is positioned comfortably, it is permissible to make an assumption regarding the gender. However, the data during this period will be approximate and their veracity is a maximum of fifty percent. The fact is that at this stage external signs are not always distinguishable, especially if the fetus’s legs are tightly together or its location does not make it possible to make an accurate forecast.
A common pathology in girls is swelling of the labia, which is mistaken for the penis. It does not require treatment and goes away on its own over time.
Folk signs will help you find out the gender of the child
Sometimes, long before the tests and the first ultrasound, relatives and acquaintances, and even the parents themselves, somehow determine the gender of the unborn child. Parents can sense their baby instinctively, while colleagues, close and distant relatives, and just acquaintances rely on all sorts of signs.
The most common:
- mothers with a sweet tooth give birth to girls, and pregnant women who prefer spicy, salty foods and all sorts of “harmful things” give birth to robber boys;
- future mothers of boys eat significantly more than mothers of girls;
- if the mother’s hair is falling out a lot, it means she’ll have a girl, increased “hairiness” all over her body means she’ll have a boy;
- Mothers with a thin waist and a beautiful face, according to the “grandfather’s” signs, should give birth to a boy, and if pigment spots appear on the face, the skin becomes uneven, reddish, the figure becomes blurred, and the legs are swollen - the likelihood that a little man will be born increases;
- the sex of the child is influenced by the month of conception and the age of the pregnant woman - even numbers of age and month of conception predict the birth of a baby, and odd numbers predict the birth of a boy;
- A high and pointed tummy is more common in women pregnant with a boy, while a low and rounded tummy is more common in expectant mothers of tomboys.
When is the first ultrasound performed?
The first ultrasound is performed at 12-13 weeks of pregnancy.
First of all, this process is aimed at a general examination of the fetus, identifying pathologies and potential risks in the development of the baby. Of course, parents are interested in gender, but even experienced specialists do not give a definite answer until 15-16 weeks, since external signs are still in the development stage and are very similar.
Ultrasound examination itself is an absolutely safe and affordable method for studying the progress of pregnancy. If problems and pathologies are detected in the early stages, doctors are able to provide timely assistance, thereby preserving the pregnancy, life and health of the mother and child.
Ultrasound at 12 weeks
Today, ultrasound is considered the most effective research method. Initially, this method is aimed at identifying early anomalies. However, during the procedure, most parents seek to find out information about the gender of the unborn child. The twelfth week is the earliest time when the sex of the fetus is visible. Until 8 weeks, a certain amount of the hormone testosterone is released.
It is formed in equal quantities in girls and boys. If a woman gives birth to a boy, then, upon reaching 2 months of intrauterine development, increased hormonal production occurs. Next, the male fetus develops testicles that synthesize dehydrotestosterone. It influences the size of the penis in the future.
For your information, the sex of the unborn child is influenced by androgens; if their activity is insufficient, the birth of a female baby occurs.
At how many weeks can you accurately determine the sex of a baby using an ultrasound?
For the most accurate results, it is recommended to contact after the twentieth week. Boys are often identified earlier - on the eighteenth, but a girl is clearly visible only after the twenty-fourth. At this time, firstly, the genital organs have already been formed, and, secondly, the fetus becomes more mobile. During the ultrasound, it changes its position, which makes it possible to examine the baby from several angles.
Determining the sex of a child is also important for specialists if the parents have chronic diseases. Some of them have a potentially negative impact on the development of the male fetus. Possible hereditary pathologies require timely identification and competent treatment.
When can you find out during pregnancy with an ultrasound?
Regular ultrasound examinations are a mandatory procedure during the entire period of waiting for the baby.
No earlier than after 4-5 months of pregnancy, the mother has the opportunity to find out who she is expecting. An ultrasound examination, which will show gender, is important in difficult pregnancies, since the principles of intrauterine treatment depend on gender.
As part of the procedure, a specialist examines the fetus from different angles. If the child is in the desired position, then his external genitalia can be traced. Errors in determining gender are usually due to the fact that:
- at the formation stage, the girl experiences swelling of the labia, which is perceived as a male organ;
- parts of the umbilical cord or fingers look like a penis;
- the boy moved his legs tightly together, covering his body parts.
The most accurate result thanks to ultrasound can be determined closer to the end of the second trimester, but there are times when there are doubts even before the baby is born. They are based on the fact that with each examination the fetus closes itself.
At what month of pregnancy is it visible
There is no clear answer to the question of at what month of expecting a child its gender is clearly visible. The following factors influence:
- Child's position. In some cases, until the last trimester, it is not possible to recognize whether the parents are expecting a boy or a girl, since during an ultrasound, the fetus is constantly in a position that is uncomfortable for the doctor.
- Quality of equipment and qualifications of specialists. Not all technology that is used today to monitor pregnancy is highly accurate.
- Similarity of signs in the early stages. Active formation of the reproductive system occurs in the second trimester of pregnancy.
In some cases, experienced specialists determine the identity by the angle between the back and the genital tubercle, which forms before the tenth week. For boys the figure is more than three hundred, and for girls it is much less. The method is not guaranteed to be reliable, but with high-quality equipment it provides information much earlier than in most cases.
If in the later stages the ultrasound does not show
In the last trimester, especially in the last weeks, it is quite difficult to determine the sex of the baby, since the fetus is already large and mainly lies in one position.
In general, ultrasound is performed at least three times during pregnancy; if necessary, the procedure is performed more often:
- at the twelfth week, when the outlines of the child are visible, it is permissible to determine the presence or absence of pathologies;
- on the twenty-second – allows you to assess the development of the fetus, including finding out the gender;
- in the middle of the third trimester, when the baby's position is checked.
If there is a burning desire to determine the gender of the baby before he is born, then it is recommended to apply for diagnostics in the second trimester. Late dates are not the optimal time for clarification. On the one hand, the child is already formed, but he is in one position and does not move.
How long does it take to find out the gender of a baby using echo signals?
On top-class sonographs with 3D/4D reconstruction, the genitals are visible from the 12th week from the moment of fertilization. The diagnosis date can be set at 3–3.5 months from the date of the last ovulation. The countdown for screening begins 15–16 days from the start of menstruation before the delay. Later, at 24 weeks, the sex of the baby will be found out at 2 ultrasounds using conventional ultrasound machines.
The first ultrasound shows the beginning of the formation of a male or female organ, how many weeks the fetus is from conception (the obstetric period is 14 days longer). As labor approaches, the baby feels cramped in the uterus. This reduces the ability to select the desired angle for scanning. After the 8th month, the sex is often invisible: the fetus obscures the genitals with its feet when presented correctly.
On an ultrasound scan at 11 weeks, a boy/girl can be distinguished by the severity of the genital tubercle and the size of the angle between the rudiment of the organ and the back of the fetus.
Ultrasound signs
Diagnosticians recommend going to determine the sex of the child based on ultrasound signs at the border of the 2nd–3rd trimester. From the 20th week, the genitals are formed. At 6 months + 10 days, the fetus is not large and often takes an accessible position for assessing the organ.
Ultrasound signs of gender:
| Age from conception | What do fetal genitals look like? | |
| boy | Girls | |
| At 11 weeks | The size of the genital tubercle is pronounced, large | The genital tubercle is less convex |
| At 12 weeks | When the penis is forming, the angle between the genital rudiment and the spine is greater than 30º The foreskin is formed | When the clitoris is formed, the angle from the genital tubercle to the spine is less than 30º. 4 longitudinal folds are visible (2 major + 2 labia minora) |
| ―16 weeks (4 obstetric months) | The scrotum is formed, the penis enlarges | The genitourinary groove does not fuse, the labia are formed |
| 5 months (from 20 weeks of age) | The male organ is formed; on the monitor it looks like a snail with a shell | Female genitals are formed. The distance between the anus and the clitoris is less than that of a boy from the anus to the penis. |
| 6-9 months | The genital organ does not change in shape, but increases in size | |
If the sex of the child is not visible, the diagnostician evaluates male characteristics based on physique. The sons have a more angular lower jaw and skull shape, the umbilical cord is dense and thick. Most often there is a lot of amniotic fluid. The development of a girl can be determined by the rounded contour line of her face and head. There is also less amniotic fluid, diameter and echogenicity of the umbilical cord.
What is the probability of error
Despite the fact that ultrasound is the most accurate method for determining the sex of a child, there remains the possibility of erroneous determination. The main reasons for inaccuracies include:
- Short waiting period for the baby. As mentioned above, in the first trimester there are no significant differences in the genital organs of boys and girls.
- Low quality of equipment and qualifications of the ultrasound specialist. Few clinics are equipped with new devices. And the doctor may confuse the fingers or the umbilical cord with the external genitalia.
- Uncomfortable position of the fetus or its increased activity under the influence of ultrasound. In the second trimester, the baby is most active and reacts sharply to external conditions, including waves.
It is recommended to conduct the study after the twenty-second week, the figure will be close to ninety percent. Often parents find out who they have born only during childbirth. This is not always due to the low qualifications of the doctor; in most cases, the reason is the poor location of the baby at the time of diagnosis.
The development of a baby in the womb is a long process. External sexual characteristics are distinguished after the tenth week, but the most accurate determination is possible only after the twentieth. As practice shows, boys are identified faster than girls.
Is it possible to find out the gender at 20-22 weeks?
At 20-22 weeks, the accuracy of the results is about 90%. The genitals have already formed and are clearly visible, and the embryo itself is mobile, and most likely the baby will be clearly visible during the examination.
Could it be that the ultrasound is mistaken about the sex of the child? This cannot be ruled out. This happens for many reasons:
- The ultrasound machine is old and gives a poor image. Doctors often make mistakes due to poor visualization of the embryo.
- Sometimes it happens that the diagnosticians themselves made a mistake due to inexperience. Sometimes insufficiently qualified specialists mistook an embryonic handle or a loop of the umbilical cord for part of the male genital organ.
- Can abnormal fetal position complicate diagnosis? There have been many cases where ultrasound was mistaken in breech presentation. A vaginal sensor would determine gender more accurately. But in this way, unless absolutely necessary, pregnant women in later stages are not examined.
- An ultrasound error in determining the sex of the child is very likely after 30 weeks. Many women think that the longer the pregnancy, the easier it will be to determine who will be born. But this is a misconception. At this stage, the fetus is already large, and it can take such a position in the uterus that it will be difficult to examine its genitals. The most appropriate time for such an examination is 22 weeks.
- Multiple pregnancies can also complicate the examination. Women expecting twins or triplets are interested in how long it takes to find out the gender of their future children. An ultrasound can answer this question starting at week 15, but a more accurate result will be obtained only at week 20. However, the likelihood of error will be higher than with a singleton pregnancy. One of the embryos may be covered by the umbilical cord or hidden behind the second fetus.
What does an ultrasound scan show at 12 weeks of pregnancy and what should be the norm?
An ultrasound at the 12th week of pregnancy allows diagnosticians to draw a conclusion about the correct development of the fetus and the condition of the mother’s reproductive organs in the first trimester. After analyzing the data, the doctor can, if necessary, take measures necessary for the further proper course of pregnancy.
Between 10 and 12 weeks the fetus is just beginning to develop, and ultrasound can help identify and prevent possible future health problems. It is necessary to examine the amniotic sac and umbilical cord. An ultrasound at 12 weeks is the first of three scheduled examinations of this type; the Ministry of Health recommends undergoing ultrasound diagnostics every trimester of pregnancy.
This screening allows you to:
- find out whether fetal development is proceeding correctly;
- understand whether the embryo has genetic pathologies;
- find out the gender of the child;
- detect ectopic pregnancy in time.
Methods of carrying out
There are two ways to perform an ultrasound at twelve weeks of pregnancy:
- Abdominal. When examining with this method, the doctor runs a sensor along the outer surface of the peritoneum.
- Transvaginal. This examination is performed when the sensor is inserted into the vagina.
The choice of method for conducting an ultrasound examination depends on the following factors:
- exact date of pregnancy;
- mother's weight;
- general condition of the pregnant woman.
An ultrasound scan takes place at a local clinic or at a private doctor. The doctor may allow the woman to choose the method of carrying out the procedure if there is no indication for examining the vagina from the inside.
Abdominal method
The abdominal method is rarely used at such a short stage of pregnancy, because due to the small size of the embryo, the resulting image is of very low quality.
Transvaginal method
The transvaginal technique allows you to most accurately examine the condition of the embryo. Also, using this method, you can reliably estimate the size of the collar area of the unborn child, deviations from the norm which may indicate the possible presence of Down syndrome.
How to prepare for the examination
Preparing for an ultrasound at 12 weeks of pregnancy includes several simple steps:
- Before the examination, hygiene procedures are required.
- If an ultrasound is to be performed using the abdominal method, you must drink at least half a liter of liquid before the examination. Thanks to this, the internal organs will expand slightly and the fetus will be better visible during diagnosis.
- You do not need to drink water before a transvaginal ultrasound. Before visiting a doctor, you should drink activated charcoal to reduce gas formation in the intestines.
For an ultrasound, a woman must bring a towel and napkins with her, and for a transvaginal examination a condom is required.
You should also take with you to your appointment with a diagnostician:
- medical card;
- medical insurance;
- passport.
What does an ultrasound show?
During an ultrasound, pregnancy development is analyzed using the following indicators:
- Formation of the umbilical cord. For the normal course of pregnancy and childbirth, there must be two arteries in it.
- Condition of the cervix and uterine walls.
- Fruit size. The size of the body, head, and the length of some bones are specified.
- The point where the baby attaches to the placenta. The optimal location should be on the side or at the bottom of the uterine wall. A different situation may give reason to recommend a cesarean section during childbirth.
- Formation of the baby's nervous system. They look at the condition and development of the brain hemispheres. This makes it possible to identify genetic diseases at an early stage.
- The position of the child's vital organs. Screening will show how the baby’s heart, kidneys, liver, and lungs are located at the initial stage.
- Formation of the brain.
- Exact gestational age.
- Amount of children. An ultrasound allows you to find out whether a woman will have twins or twins.
- Work of the heart.
In the video provided by the Sparrow Family / Life of a Large Family channel, you can see what a baby’s fetus looks like at the 12th week of pregnancy.
With an ultrasound at 12 weeks, the baby’s movements can already be tracked. Its activity starting from 7–8 weeks of pregnancy is an important indicator of development.
Ultrasound procedure
With transvaginal and abdominal methods, the ultrasound examination procedure is carried out in various ways.
Transvaginal ultrasound examination proceeds as follows:
- The woman should expose her lower body for ease of insertion of the sensor.
- A condom is placed on the transvaginal sensor and lubricated with gel.
- An ultrasound probe is passed through the woman’s reproductive organ.
- The sensor transmits data to the monitor using an ultrasonic wave.
- The information received is analyzed by a doctor.
This method allows you to get close to the baby and professionally determine the parameters and characteristics of the fetus. At the same time, the ability to correctly determine the sex of the child increases.
The abdominal method involves the following stages:
- The woman exposes the abdomen.
- The sensor is treated with gel and moved over the pregnant woman’s abdomen.
- The monitor displays a picture of the study, where you can see the outlines of the unborn child.
- The specialist takes indicators of the fetus’s condition and enters them into the ultrasound protocol.
- The result is checked by a diagnostician and reported to future parents. The doctor also gives them pictures of the baby.
Decoding the results
Diagnosticians and geneticists are engaged in a detailed interpretation of the research results. Only they can give professional answers and recommendations at the end of the procedure.
There are several basic normative values that are used as a guide when performing an ultrasound:
| Parameter | Normal at 12 weeks of pregnancy |
| Height | 8–10 cm |
| Weight | up to 19 grams |
| Thigh length | 7–9 mm |
There are also certain norms specific to the 12th week of pregnancy:
- KTR;
- BPR;
- TVP;
- nose length;
- Heart rate;
- embryonic structures.
KTR norms
The coccygeal-parietal size, or abbreviated CTR, is the maximum distance that can be measured from the head to the tailbone at 10-14 weeks. CTE is the most accurate parameter for determining the duration of pregnancy. Normally it should be from 51–59 mm.
Norms of BPD of a child's head
Bi-parental size (or BPR) allows you to determine the size of the head, and therefore the level of development of the child’s brain. BPR is the width of the head, measured along the minor axis, from temple to temple. Normally it should be 21 mm.
Neck fold size, or TVP
The thickness of the collar space (or neck fold) in a child should be from 1.6 to 2.5 mm.
Norms for the length of the nose and nasal bone
A twelve-week-old fetus has a nose (nasal bone) 3 mm long.
Heart rate norms
The heartbeat is the main indicator of the vitality of the unborn child, which reflects its condition and changes if any unfavorable situation arises. The heart rate should be 150–174 beats per minute.
Standards for the study of embryonic structures
Extraembryonic structures are:
- Yolk sac. A provisional organ that performs various functions in the body of the embryo until the corresponding organs are formed (for example, the liver and spleen). By the 12th week, the yolk sac should not be visible; by the 10th week it may look like a white ring up to 7 mm in size.
- Chorion. The outer shell of the embryo is formed in the first days after conception and ensures the exchange of substances between the body of the mother and the baby throughout the pregnancy. The chorion has the appearance of a white ring with villi. Its thickness in millimeters in digital value is approximately equal to the woman's gestational age in weeks.
- Amnion. The aqueous membrane that fits tightly to the chorion. The amniotic material must form correctly. Its developmental pathology may be associated with an infection in the mother's body.
The correct formation of these structures affects the entire course of pregnancy, as well as childbirth and the health of the baby.
Possible pathologies
Ultrasound examination for pregnant women is a way to find out about possible pathologies in time and take medical measures if necessary.
Deviations from the norm
Deviations from the norm during this period are considered:
- Greatly increased TVP. In addition to the thickness of the collar zone, the length of the nose is checked; its shortening (hypoplasia) indicates the development of pathology.
- For doctors, a dangerous sign is the underdevelopment of the yolk sac (if it is less than 7 mm) and the size of the chorion and amnion at 6 weeks is less than 10–12 mm.
- The heartbeat in pathologies can be either greatly reduced (85–100 U/m) or very high – up to 200 beats per minute.
Symptoms of genetic abnormalities
Genetic abnormalities occur during the process of conceiving a child, when two single-chromosomal sperm fertilize the mother's egg.
An ultrasound can show the following diseases:
- Down syndrome;
- triploidy (the presence of 69 chromosomes in each pair instead of 42);
- Edwards syndrome;
- Patau syndrome;
- Turner syndrome.
More detailed descriptions of genetic diseases and their consequences:
| Genetic disease | Manifestations in appearance | Intelligence and mental state | Forecast |
| Down syndrome. The chromosomes of the 21st pair are represented by 3, not 2. |
|
| Socialization is possible in case of constant attention and care. Life expectancy is up to 60 years. |
| Patau syndrome. Trisomy on chromosome 13. |
| Thought and speech are not present | Life expectancy is from 3 to 5 years. However, more than 95% of patients survive only up to a year. |
| Edwards syndrome. Trisomy on chromosome 18. |
| There are different degrees of mental retardation:
| 90% of patients survive only up to a year |
| Turner syndrome. Mutation of the X chromosome. |
|
| Treatment is possible. A course of hormonal medications is prescribed. But most patients cannot have children. |
What signs are used to determine the gender of a child?
At 12 weeks of pregnancy, the sex of the child is not determined with one hundred percent probability using ultrasound - the baby’s physiology is not yet sufficiently developed, and it is difficult for the doctor to give an unambiguous answer. The baby himself can help the doctor with this if he is in a position comfortable for the ultrasound examination. Then the specialist will be able to see the developing genital organs of the fetus.
Definition of boy
To confirm pregnancy with a boy, the doctor must see the rudiments of the genital organs of the male fetus.
If it's a boy, the ultrasound shows:
- A tubercle (labioscrotal eminence) between the baby’s legs. There is an angle of thirty degrees between this hill and the child’s back.
- The jaw is shaped like a square.
- In a pregnant woman, the placenta is on the right side of the uterus.
Definition of a girl
If a woman is having a girl, an ultrasound will show:
- the placenta is on the left side of the uterus;
- the skull and jaw are visually similar to a circle;
- the genital organ has transformed into the clitoris from the genital fold, and the labia are already noticeable;
- The angle between the genital tubercle and the back is less than 30 degrees.
How are twins determined?
It is possible for a woman to become pregnant with twins. There are monozygotic and dizygotic pregnancies. In the first case, the children are very similar to each other and are always of the same sex. Dzygotic twins are often born opposite sexes.
A doctor can determine a multiple pregnancy based on the following parameters:
- two heads of children are displayed on the display;
- a woman’s uterus enlarges at very early stages;
- a depression appears in the structure of the uterus.
To hear the heartbeat of the twins, phonocardiography is prescribed. This study can be done at the twentieth and earlier weeks of pregnancy.
Photo gallery
Photo of a girl, about 12 weeks Photo of twins Ultrasound photo, girl Ultrasound photo, boy Photo of a boy, 12 weeks Difference in ultrasound images of a boy and a girl
This good quality video, presented by the Doctor Nikolaev Medical Center channel, will help you learn more about how an ultrasound is performed and the gender of the child is determined.
Source: https://hromosoma.com/uzy/uzi-12-nedel-beremennosti-30733/
Ultrasound signs of the fetal genital organs at 12 weeks
Another method of assessing the external genitalia has the following characteristics: in a boy, when scanning in the transverse plane, the genitals are determined in the form of a cone with a hyperechoic apex and a hypoechoic base, merging with the ultrasound image of the bladder.
When scanning in a transverse plane, a girl’s external genitalia can be represented by one of two types:
- Type 1 - in the form of four parallel hyperechoic lines with hypoechoic spaces between them. This type of image is typical for fetuses with a small clitoris relative to the labia;
- Type 2 - in the form of a rounded cone with hyperechoic sides and a hypoechoic space between them. This type of image is characteristic of an enlarged clitoris and small labia in female fetuses.
Expectant parents should not take the results of determining the sex of the fetus too seriously at the 12th week of pregnancy and even later, since there are many reasons why an ultrasound doctor cannot give an answer to this with an absolute guarantee. And the love of parents for their future baby should in no way depend on whether it is a boy or a girl - all children are good!
Why is it not always possible to see the gender of a child?
Using an ultrasound, you can see the baby inside the uterus, but it is not always possible to see it completely. This depends on the quality of the research apparatus itself, the qualifications of the specialist conducting the examination, and the experience of the doctor. The most modern devices can even show the presence of a fluff in the place of future eyebrows, while devices 10 years ago will not show the gender of the child before the 20th week.
The baby himself is still very small, and it is quite difficult to display his size on the screen with high magnification. The image is distorted due to high magnification and movements of mother and child; they may not allow you to closely look at the small folds of the baby.
Some babies actively move or turn their backs, which prevents gender determination. The position of the fetus inside the uterus may not make it possible to determine the sex until birth, but in most cases an experienced doctor will be able to find the desired position of the head of the device and find out the secret.
