Question

how is the sex of the offspring determined in the zygote

Answer 1

Sex Chromosomes play an important role in Sex determination.There are 23 pairs of chromosomes among them 1 pair is sex chromosomes in human.The female contains 2 X chromosomes while male contains one x and 1 y chromosomes.
If x of male and x of female fuses the resulting offspring would be female.If Y of male fuses with x of female the off spring would be a male.So sex is determined by the chromosome of male.

Answer 2

Sex chromosomes were also known as allosomes.there are 23 pairs of chromosomes are there in our body.in that 23 pairs 22 pairs are vegitative chromosomes and 1 pair is sex chromosomes. In female in thaat 1 pair of chromosomes 1 will be X and another chromosome also X only. In male in that pair of chromosomes 1 will be X and other will be Y. When a male and female was met each other sexually then these chromosomes fuses with each other If male chromosome X+female chromosome X =XX ( girl) if male chromosome Y+female chromosome X=XY(boy) Like this the sex chromosome of a male will deytermine the sex of the off spring.