You may not be 50/50 likely to be a boy or a girl

You can assume that a woman’s son or daughter is likely to be 50/50, which is like a toss, but it seems that some women can be more likely to have only one sex.

“From personal experience, I have seen a friend [and] Seven Wang at Harvard University says family members who have only girls or boys.

The proportion of boys from girls at birth is about 50:50 at the population level, the main reason is that men’s sperm is equally likely to contain an X or Y chromosome, which determines the sex of the baby.

But Wang and his colleagues wondered if women could play their role too. To learn more, they analyzed data collected from more than 58,000 mothers in the United States, who had previously enrolled in two separate contraceptive and maternity health studies. Of these women, 61 % had two children, 30 % had three children, 8 % had four children, and the remaining women had five or more.

Researchers compare women’s children to eight maternity properties: height, body mass index, breed, hair color, blood type, chronatype (day of day when they are the most vigilant), the first menstruation age and their age when their first baby was 13 to 48 years old.

The team found that the women who were born for the first time were more than 28 years old when only one was likely to have a 43 % chance of having sex, compared to 34 % of those who became the first mother.

“We found that in the first birth was associated with maternity age age [a higher chance] Wang says that being just girls or boys.

Wang says that although it is unclear why this maternity age may have this effect, it may come to biological changes within the body, which may vary in women. For example, previous studies suggest that the first phase of menstruation decreases with age, which can be in favor of boys, while a decrease in vaginal pH with age can support the survival of the sperm containing X chromosome, which is more likely to be a girl.

Joshua Weld says at Oxford University, but these results can also be explained by the behavior factors. He says it is possible that older women are more likely to plan their family size. This may mean that even if they want two children of different sexes, they can decide to stay after producing two boys or two girls, while a little woman may be more likely to have a second sex child with less concern about family size.

Waleed says more studies are needed to analyze how behavior, environmental and biological factors affect the child’s sex.