Question

In humans, the sex of the baby is determined_________.

• A. at the time of implantation and by the maternal gamete
• B. at the time of implantation and by the paternal gamete
• C. at the time of fertilization and by the maternal gamete
• D. at the time of fertilization and by the paternal gamete

Answer 1

The correct option is D at the time of fertilization and by the paternal gamete

Sex determination occurs at the time of fertilization and only by the father in humans. Father has heterogenous sex chromosomes X and Y, while in the case of mother, they have homogenous sex chromosomes XX .The possible combinations are XX, XY, XY and XX with the mother being the contributor of X chromosome only in all the four combinations. Hence, embryo’s sex is decided by the father's X or the Y chromosome present in the sperm that fertilizes the egg.