Question

how is the equal genetic contribution of male and female parents insured in progeny

Answer 1

During sexual reproduction , a female gamete ( having 23 chromosomes) fuses with male gamete having 23 gamete to form zygote. zygote is diploid which contain 23 chromosomes from father and mother. In this way an equal contribution of male and female parents insured in progency

Answer 2

How is the equal genetic contribution of male and female parents ensured in the progeny?

During the formation of gametes as a result of reductional division (meiosis), sperms - XY & eggs - XX receive only single genome of a parent.

When fertilization occurs, one genome each from sperm & egg reaches the zygote.

It means both male & female parents contribute exactly equal amount of genetic material to the offspring.