In India, men sometimes get upset when they getting the girls and blame the mother of having some deficiency.
Sex of the baby is determined by whether she carries two X-chromosomes (then it would be a girl) or an X and Y (then it would be a boy).
Mother's egg always contributes ONLY X-chromosome. A man, on the other hand, can produce sperms that have either an X or a Y-chromosome. Sperms compete to fertilize the egg, and it is pure chance whether a sperm with X or sperm Y enters the egg.
X-chromosome is three times bigger (155 million base pairs) than Y-chromosome, so Y-chromosome is slightly lighter (not 1/3rd because there are 22 other chromosomes that are of equal length in both the egg and the sperm) and should be faster in reaching the egg. One would expect more boys conceived as a result. Boy babies are only slightly (1.2%) more likely than girl babies, however, because male fetuses are less likely to be carried to term than female ones.
Sex of the baby is determined by whether she carries two X-chromosomes (then it would be a girl) or an X and Y (then it would be a boy).
Mother's egg always contributes ONLY X-chromosome. A man, on the other hand, can produce sperms that have either an X or a Y-chromosome. Sperms compete to fertilize the egg, and it is pure chance whether a sperm with X or sperm Y enters the egg.
X-chromosome is three times bigger (155 million base pairs) than Y-chromosome, so Y-chromosome is slightly lighter (not 1/3rd because there are 22 other chromosomes that are of equal length in both the egg and the sperm) and should be faster in reaching the egg. One would expect more boys conceived as a result. Boy babies are only slightly (1.2%) more likely than girl babies, however, because male fetuses are less likely to be carried to term than female ones.
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