Question

mothers give birth to a baby but the baby has the characterstics of both parents. How is this possible?

Answer 1

The baby is developed from an embryo. Embryo is developed from a zygote.
Zygote is formed by the union of male and female gamete. that is sperm and ovum.
Sperm contains male body chromosomes and ovum contains female body chromosomes. Therefore baby always had recombined genes of both parents

Answer 2

Because a  female produces X chromosome in egg and a male sperm has either X or Y chromosome so when there is a  mating between opposite sex it leads to a  fusion of both chromosome