Question

Give reasons for the following:

(iii) It is a matter of chance whether a couple will give birth to a boy or a girl.

Answer 1

1. Humans have 22 autosome pairs and one sex chromosome pair.
2. X and Y carrying gametes or sperms are produced by the male parent while the female parent produces only X carrying gametes or eggs.
3. When one X having gamete from males and one X bearing gamete from females are combined during reproduction, offspring with the genetic constitution XX are produced.
4. The child born is a daughter or a female.
5. When Y chromosome of males is combined with one X chromosome of females, the outcome is an offspring with the genetic constitution XY. The child is either a son or a male.
6. As a result, whether a boy or a girl is born is entirely dependent on the type of sperm that fertilizes the egg.