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Sex Determination in Humans

Sex Determination in Humans The mechanisms for sex determination are genotypic sex determination systems, in which sex is governed by the genotype of the zygote and environmental sex determination systems in which sex is governed by internal and external environmental conditions. In genotypic sex determination the sex chromosomes play a decisive role in the inheritance and determination of sex. Chromosomal sex is determined at fertilization. Sexual differences begin in the 7th week. Sex is influenced by genetic and environmental factors. Females (generally XX) do not have a Y chromosome. Males (generally XY) have a Y chromosome. Sex determination mechanism is humans is XY type. 22 pairs are similar in male & females whereas presence of X/Y chromosomes determine human sex. In spermatogenesis male produce 50% of sperms with X-Chromosomes and the other 50% with Y-Chromosomes. Female have only X-Chromosomes. It is hence a matter of chance, since there is equal probability of getting fe