SSC MTS EXAM

Detailed explanation-1: -If the sperm that reaches the egg has an X chromosome, the zygote will have, an XX sex chromosome, Since the ratio of the X chromosome and Y chromosome in a male gamete is 50:50, the probability of male or female infants is also 50:50.

Detailed explanation-2: -If the egg receives another X chromosome from the sperm, the resulting individual is XX, forms ovaries, and is female; if the egg receives a Y chromosome from the sperm, the individual is XY, forms testes, and is male. The Y chromosome carries a gene that encodes a testis-determining factor.

Detailed explanation-3: -Each time a sperm meets an ovum, there is a 50% chance that it will make a boy and a 50% chance that it will make a girl. It doesn’t matter what happened the time before that: each time an ovum is fertilized, this makes a new zygote that could be a boy or a girl.