BOY OR GIRL: HOW GENETICS DETERMINE YOUR BABY'S GENDER
So that you are pregnant now, what is the next big surprise for you? The baby! Is it a boy or a girl? This is probably the next big question for you. Some of us long for a boy and some of us yearn to have a baby girl. But the matter of fact is that it is probably something beyond our control. We can only wish. It is the fate which decides which gender our baby will have. Nature keeps its balance. There is always an equal chance that you will have a baby girl or a baby boy. Behind this game of probability lies a complex interplay of genetic factors which ultimately determine the gender of your baby. In the literature to follow, how genetics determine the gender of your baby shall be explained.
Gender of a baby is determined by the presence of a specific set of genetic materials called sex chromosomes. The sex chromosomes in the cells of a baby determine the baby’s gender. A boy has YX combination of sex chromosomes while a girl has XX combination of sex chromosomes. Now let us trace the baby to the time they are conceived as a fertilized egg. As you may already know, a sperm from your husband fertilized your egg which got implanted in your uterus to become an embryo and later a fetus. Your husband’s sperms and your eggs unlike all other cells of the body have only one sex chromosome. Your eggs always carry the X chromosome without any exception. On the other hand, your husband’s sperms also carry one sex chromosome but unlike you, half of the sperms he produces carry an X chromosome while the remaining halves have Y chromosomes.
So now take some probability into consideration. Since half of your husband’s sperms carry an X chromosome and the other half a Y chromosome, there is an equal chance of each of the two types of sperms fertilizing your egg. If the one having an X chromosome fertilizes your egg, the resulting embryo will have an XX configuration and shall develop as a female fetus. On the other hand, if a sperm carrying a Y chromosome fertilizes your egg, the resulting baby shall have an XY configuration making it a male embryo. So basically the genetic determination of baby’s gender is dependent upon the male partner.
Now you may be wondering that there is an exactly equal chance that you will bear a boy. Based on the genetic mechanism just explained, there can be a few exceptions. Research shows that since the Y chromosomes are smaller than the X chromosomes in size, sperms carrying them are lighter and may swim faster than the heavier X chromosome containing sperms. As such, they can probably swim to the egg earlier than the sperms with X chromosome. Furthermore, some research also shows the effects of determinants like diet, socioeconomic status, and lifestyle on the determination of baby’s gender but the evidence is quite limited and cannot be put to use at this point in time.
You may have heard about advertisements and research going on about baby’s gender selection. After reading about the genetic basis of gender determination, you must be wondering how gender can be artificially selected when it is totally unpredictable that which sperm will fertilize an egg, an X-sperm or a Y- sperm. Recently scientists are researching on determining the variation in the physical properties of sperms like the swimming differences in X-sperms and Y-sperms we described above. These differences are being exploited to choose baby’s gender in an experimental phase though their guarantee and promise is quite limited.
To conclude, being a woman, you have almost no role in determining the gender of your baby. Genetics control your baby’s gender through your husband. So don’t panic for the gender, all you need to have is a good womb which takes care of the baby for the first nine months of his or her life.