Sex of the baby is determined by the father not by the mother substantiate.

Explanation

Sex chromosome of females are XX. Hence all the ova carry X chromosome. Males are heterogametic (XY). Hence `50%` sperms carry X chromosome and 50% carry Y chromosome. A male child is developed when a Y-sperm fertilises the ovum and a female child is formed when the X-sperm fertilises the ovum. Therefore, the statement that the sex of the baby is determined by the father and not by the mother is true.