It suggests that an as-yet-undiscovered gene controls whether a man's sperm contains more X or more Y chromosomes, which affects the sex of his children. Looking at how sperm cells impact the sex of the baby is key to unraveling why some women have only boys and others have only girls.
A baby's biological sex is determined by the two sex chromosomes in the egg and sperm. Eggs always have an X chromosome, and sperm have either an X or a Y chromosome. Whichever sperm is the winner will penetrate and fertilize the egg, creating either an XX (girl) or XY (boy) pair.
Deep penetration, for example doggy style, means the male sperm that can swim faster start their race closer to the cervix and are more likely to reach the egg first, resulting in a boy. To try and conceive a girl, Shettles suggested avoiding deep penetration, favoring the missionary position.
Among 132 families that had three children of the same sex, 69 went on to have another child of that sex, and 63 went on to have a child of the opposite sex. The chance of having a girl after two boys was about 48 per cent and the chances of having a boy after two girls was slightly lower, at only 46 per cent.
There are lots of theories and claims made about influencing the chances of having either a boy or a girl baby, but the scientific facts are absolutely clear. The chances of having conceiving a boy or a girl are almost exactly equal for each and every pregnancy.
Speed: since sperm containing the Y chromosome are faster than those containing the X chromosome, if the egg is in the fallopian tube at the time of intercourse, there is a greater probability of a Y sperm reaching and fertilising it, which means there is a greater probability of the baby being a boy.
While historically, there have been about 105 boys born for every 100 girls worldwide — which creates a “sex ratio at birth” of 1.05 — the share of boy babies has increased in recent decades.
Dr Michael Thomas MD (fertility specialist) actually advises that there are no methods to affect the sex of your child, including sexual position.
However, a 2018 Gallup poll found that 54% of Americans said boys were easier to raise than girls, while only 27% said girls were easier, and 14% said there was no difference. Some research suggests girls are better communicators in the younger years, but this may change later on.
But that's not exactly true – there's actually a slight bias toward male births. The ratio of male to female births, called the sex ratio, is about 105 to 100, according to the World Health Organization (WHO). This means about 51% of deliveries result in a baby boy.
Consider having a baby before your reach 30 or 35.
Therefore, if you're trying for a boy, it might be best to start early. The chances are highest for a woman to conceive a boy before age 30. It's age 35 for men.
It suggests that an as-yet-undiscovered gene controls whether a man's sperm contains more X or more Y chromosomes, which affects the sex of his children. Looking at how sperm cells impact the sex of the baby is key to unraveling why some women have only boys and others have only girls.
It is simply a matter of chance as to which category of sperms fuses with the ovum. If the egg (X) is fused by X-bearing sperm, the resulting combination is XX, i.e. female type, and the child produced is female (daughter).
Because male sperm is the faster of the two, Shettles suggests having intercourse as close to ovulation as possible, so the male y sperm can reach the egg first. If you have sex several days before the day of ovulation, the less resilient male sperm may die off. This leaves more female sperm to fertilize the ovum (5).
Sons are easier to raise, daughters not so much
According to Parents, gender matters when it is about raising children. Mothers have found girls to require a lot of emotional handling even from infancy. But boys are more easy-going and emotionally stable.
Every stage of parenting has its challenges, but one poll reveals what age most parents feel they struggled with the most.
Moms who have girls are much happier than those with boys, particularly when the children reach early adulthood, according to a study from the Journal of Family Issues. However, a survey done by Gallup says: 54% of Americans say boys are easier to raise than girls. 27% say girls are easier to raise than boys.
Sex selection in IVF is not legally allowed in Australia for reasons of family balancing.
This study finds that the gender preference affects the fertility and reproductive behavior of the respondents and it is necessary to reduce son preference for the health and well being of children and women.
There is a clear pattern of births across latitude. Here in the U.S., states in the North have a birth peak in early summer (June-July), while states in the South experience a birth peak a few months later (October-November).
Nature is designed to favour the conception of boys from September to November and girls from March to May because of an evolutionary mechanism aimed at keeping the overall sex ratio as near to 50:50 as possible, the scientists said.
And the mean reached a high of 27.3 years in 2021, up from 27.1 in 2020.