How is the sex of an offspring determined in the zygote in human beings? Explain with suitable diagram showing the cross between male and female gametes.

Zygote is a diploid cell having 2n chromosomes. Zygote is a very early stage of sex determination and the sex determination can take place at embryo level in practical world. Theoretically for sex determination at zygote level is as follows:

Male is bearer of XY chromosome. Female is bearer of XX chromosome. From this we can understand that female chromosome does not decide the sex of the zygote/offspring. The pairing of male chromosome X with female chromosome X i.e XX pairing will result in female zygote/offspring and male chromosome Y pairing with X chromosome from female i.e XY pairing will result in male zygote/offspring.