8. Write notes on—
(c) Sex determination in the unborn baby.
Sex determination of baby-
All humans have 46 number of chromosomes with 23 pairs. Out of these, two chromosomes, X & Y are the sex chromosomes. A female has two X and a male has one X and one Y chromosome. Female gamete ovum and male gamete sperm have possess only one set of chromosomes. The unfertilised egg always has one X chromosome, however, sperms can have two different kinds of chromosomes. They can have either an X chromosome or a Y chromosome. When a sperm of X chromosome of male fertilises the egg (X chromosome), the zygote would have two X chromosomes and develop into a female child. But if the sperm contains a Y chromosome and fertilises with the egg (X chromosomes), the zygote would develop into a male child (XY).
Hence it is clear that the sex of an unborn baby is determined by the father's sex chromosomes.