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NEETBiologyPrinciples of Inheritance and VariationClass 12

What does “Sex determination (XX-XY)” actually mean in Principles of Inheritance and Variation, and why does it matter for NEET?

human females are XX and males XY, so the father's sperm (X or Y) decides the child's sex.

In simple words: human females are XX and males XY, so the father's sperm (X or Y) decides the child's sex. Getting Sex determination (XX-XY) clear matters because NEET questions on Principles of Inheritance and Variation usually test this idea directly, not just a formula you memorised.

Key point

Sex determination (XX-XY)

Common mistake

blaming the mother for the sex of the child.

Memory tip

mother gives only X; the father's X- or Y-bearing sperm sets the sex.

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