Male longevity risk pregnancy women big time

Prepared childbirth to pregnant women from the longer a fetus, the greater the chance of a boy, which may carry the sperm sex chromosome movement on faster.

Boy female longevity greater the chances of conception of time from preparation to childbirth to pregnant women on the longer the fetus, the greater the chance of a boy, which may carry the sperm sex chromosome movement on faster.

Every 105 boys born, only 100 girls born. One view is that this may be related to sperm chromosomes as sex chromosomes determine sex male Y sex chromosome than the female X decided to carry less DNA, which makes the sperm carrying Y chromosome in the female cervical mucus in the swimming speed faster. Luke Smith Maastricht University Heights that the time when the cervical mucus is extremely thick, these women may take a long time, several attempts to conceive, with a "light" Y chromosome sperm advantage of this time even more obvious, so likely a boy is too large.

 To test this theory, Smith Heights surveyed 5,283 30-year-old woman. In the 498 years after a natural way of time before the fetus pregnant women, 56% gave birth to boys. In a year pregnant women, the proportion of boys was 51%. Smith Heights, obtained by calculation, the natural way of conception, to spend 1 year each time, a boy will likely increase by 4%.