It reveals genetic information about your baby. You can have this test as early as your 10th or 12th week of pregnancy. And because it has gene information about your baby, it can also reveal the sex of your baby. This is an accurate test for finding out the sex of the baby, but it does involve some risks. Amniocentesis is a test that helps diagnose detect developmental issues in a fetus.
Your doctor collects a small amount of amniotic fluid, which contains cells that indicate abnormalities. The cells are tested for Down syndrome, spina bifida , and other genetic conditions. You can have this test around 15 to 18 weeks of pregnancy, and it takes about 30 minutes. Risks include cramping, bruising, and spotting.
Along with detecting birth defects and other abnormalities with your baby, an amniocentesis also identifies the sex of your child.
Since an ultrasound creates an image of your baby, it can also reveal the sex of your baby. Most doctors schedule an ultrasound at around 18 to 21 weeks, but the sex may be determined by ultrasound as early as 14 weeks.
Your baby might be in an awkward position, which makes it difficult to clearly see the genitals. But mistakes do happen. Some of these tests according to claims can determine the sex as early as 8 weeks, with about 99 percent accuracy.
This is how it works: You take a sample of your blood, and then send this sample to a lab. The lab checks your blood sample for fetal DNA, looking specifically for the male chromosome. Keep in mind that when sending samples through the mail to an unknown lab there are many factors that may reduce the reliability of the results.
These tests tend to be expensive so you may want to consider whether they are worth the cost for you. This means that women can only make eggs with an X chromosome. But men can make either X or Y sperm.
During fertilization, the sperm cells race toward the mother-to-be's egg cell. If a sperm with a Y beats all others, then the fetus will be XY. The pregnancy will result in a boy. However, if a sperm with an X wins the race to the egg, then the fetus will be XX. The parents will have a baby girl. And yet, we all know families that are all boys or all girls. Having all boys or all girls is almost always due to simple chance.
It is only rarely that parents have one sex more often than another for some underlying biological reason. You've probably flipped a coin to make a decision between two things before. These are about the same odds as having a boy or a girl. What if you flip a coin ten times and get heads every time? What are the odds for heads on the next coin flip? In a coin flip, it doesn't matter what came before. This is because the coin can't remember what was previously flipped.
The same thing is true in having a boy or a girl. Mom's body can't remember what sex the previous child was. It's just a matter of which type of sperm happens to reach the egg first. In families that have all boys or all girls, it turned out to be the same one each time. And if they decide to have another child, the chances are that the baby will be a girl versus a boy. In the real world, though, more than chance is involved. As we talked about earlier, other factors can affect which sperm makes it to the egg and whether the fertilized egg goes on to be a healthy baby.
Most factors in people are thought to be very small though. Remember how we said that more boys are born than girls because of the speedier boy sperm? Well the difference is actually not that big However, the animal world is a whole different story. All sorts of things can happen so that more boys are born than girls and vice versa. Animals with Wacky Sex Ratios Based on a number of factors, some animals alter the sex ratio of their offspring.
So in the same way that the gene may cause more boys to be born after wars, it may also cause more boys to be born each year. The trees above illustrate how the gene works.
It is a simplified example, in which men either have only sons, only daughters, or equal numbers of each, though in reality it is less clear cut. It shows that although the gene has no effect in females, they also carry the gene and pass it to their children.
In the first family tree A the grandfather is mm, so all his children are male. He only passes on the m allele, so his children are more likely to have the mm combination of alleles themselves. As a result, those sons may also have only sons as shown. The grandsons have the mf combination of alleles, because they inherited an m from their father and an f from their mother.
As a result, they have an equal number of sons and daughters the great grandchildren. In the second tree B the grandfather is ff, so all his children are female, they have the ff combination of alleles because their father and mother were both ff. One of the female children has her own children with a male who has the mm combination of alleles. That male determines the sex of the children, so the grandchildren are all male.
The grandsons have the mf combination of alleles, because they inherited an m from their father and f from their mother. As a result, they have an equal number of sons and daughters the great-grandchildren. Materials provided by Newcastle University. Note: Content may be edited for style and length.
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