WHAT IS SEX INHERITANCE? explain sex inheritance

-in human sex is determined by a pair of chromosomes called sex chromosomes (X and Y)
-because these chromosomes do not look alike they are sometimes called heterosomes
-all other chromosomes (apart from sex chromosome are called autosome and they determine all other characteristics or traits except sex hence 22 pairs out of the 23 pairs of chromosomes are autosomes
-the female produce only one set/kind of ovum/egg
-each containing an X-chromosome which are similar in all respect
while the male produces two different/unidentical spermatozoans
-one containing an X-chromosome and the other a Y-chromosome
-two possibilities occur during fertilization
-either a female offspring (XX) or male offspring (XY)
-the XX (female offspring) results when a spermatozoan bearing an X-chromosome fertilizes an ovum also bearing an X-chromosome-fertilizes the ovum
-the XY (male offspring) results when a spermatozoan bearing Y-chromosome
-the chance of female (XX) to male (XY) is 50%:50%
-hence the father determines the sex of the child.

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