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🩺 NEET🧬 Biology

Sex is determined in human beings

Q1 FREE PREVIEW
Sex is determined in human beings
aBy ovum
bAt time of fertilisation
c40 days after fertilisation
dSeventh to eight week when genitals differentiate in fetus.
✓ Correct answer: b) At time of fertilisation
ExplanationThe sex of a human baby is genetically determined at the exact moment of fertilization (conception), when the sperm and the egg fuse.The egg (ovum) always carries an X sex chromosome.The sperm carries either an X or a Y sex chromosome.The combination at fertilization dictates the genetic sex:If an X-carrying sperm fertilizes the egg, the zygote is XX (female).If a Y-carrying sperm fertilizes the egg, the zygote is XY (male).While the physical differentiation of genitals occurs much later in fetal development (around the 7th to 8th week), the underlying genetic blueprint for sex is set immediately at fertilization.
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