The highest pregnancy rates occur in couples who have sex every day or every other day. Have sex near the time of ovulation. If having sex every day isn't possible — or enjoyable — have sex every 2 to 3 days a week starting soon after the end of your period.
When I tell patients there's about a 50/50 chance for either sex, I also tell them the father's genes determine the baby's sex since some of his sperm carries X chromosomes and some carries Y chromosomes. That's with the assumption, though, that the man's sperm carries equal numbers of X and Y chromosomes.
The Whelan Method
So if they're hoping for a boy, the theory says, couples can try to have sex four to six days before ovulation. And to conceive a girl, they can hit the sheets either two to three days before ovulation or on the day the woman ovulates.
On average, a woman with a regular 28-day cycle ovulates on about the 14th day of each cycle. If a woman's cycle is longer or shorter than 28 days, the predicted ovulation date is changed accordingly. For example, during a 24-day cycle (4 days shorter than the average), ovulation takes place on about the 10th day.
Sperm carrying a Y seem to swim the same speed as sperm carrying an X. But other factors like how mom or dad lives can affect the sex of their baby. A number of studies have suggested that factors like nutrition, wealth, and even where the parents live can affect the odds of having a boy or a girl.
02/6The study. On an average, couples have sex 78 times from the time they start trying to the time they get a positive result. These 78 times are spread over 158 days or about 6 months. A study surveyed 1,194 parents and found that most couples have sex 13 times a month while they are trying to conceive.
Fertility. Most couples will get pregnant within a year if they have regular sex and don't use contraception. But women become less fertile as they get older. The effect of age on men's fertility is less clear.
Since sperm are equally divided into X and Y chromosome sperm, the chances of having a boy or a girl should be equal. So why do some families have all girls or all boys? Each time a sperm meets an ovum, there is a 50% chance that it will make a boy and a 50% chance that it will make a girl.
“What we have been taught conventionally is that — bar any genetic disorders that cause early pregnancy loss that only affect girls or boys — there is always a 50/50 chance of one or the other gender each time. The chance of a girl after three boys is still the same probability.”
When we look at the statistics the chances of having a boy or a girl are almost the same and there's no medical evidence to suggest we can influence this. You may, however, have heard about the 'Shettles Method'.
You're most fertile at the time of ovulation (when an egg is released from your ovaries), which usually occurs 12 to 14 days before your next period starts. This is the time of the month when you're most likely to get pregnant.
The bottom line is that a single act of intercourse between a young couple has on average a one in 20 chance of pregnancy – this assumes the opportunity presented itself on a random day, as these things tend do when you are young.
The scientists also note that at the age of 35, the proportion of sperm carrying an X chromosome also seems to increase, meaning older dads are more likely to have daughters. In human reproduction, the Y chromosome is responsible for making a male child.
Some studies claim that a man's sperm count is higher in the morning, but the differences are so minimal, it doesn't matter much in terms of getting pregnant. Say your mate's sperm count goes from 87 million in the evening to 88 million in the morning.
Some scientists think whether you're likely to have a girl or boy is inherited through the father, although nobody has identified a gene. Others have suggested that it comes down to heritable traits that could confer an evolutionary advantage on one sex, but not the other, when it's time for offspring to reproduce.
There are also both personal and environmental factors that affect the average sex ratio. The chance of having a boy appears to decline with the mother's age, the father's age and the number of children the family already has.
Men inherit their tendency to have sons or daughters from their parents: Study. The study suggest that there is an undiscovered gene, which determines whether a man's sperm contains more X or Y chromosomes, which ultimately impacts the gender of his children.
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.