Interesting Gender Stats

texasmama786

The 51/49 Boy/Girl Ratio The ratio of 51% boys to 49% girls seen here is representative of overall US birth rates. There are many hypotheses about why there are slightly more boys born each year than girls, but no one knows for sure why this is so. Here are a couple of the theories: Males are more fragile (male infants are less likely to survive their first year, and a man's expected lifespan is less than a woman's). The slightly higher conception rate of males is nature's way of evening out the balance. As Shettles contents, Y-bearing male-producing sperm may have a speed advantage over X-bearing female-producing sperm, more often winning the race to fertilize the egg and resulting in more male conceptions. Regardless of the reason, the 51/49 ratio remains constant year to year throughout the US population. Are Boys or Girls Preferred? The Chance study describes "stopping behavior" -- the tendency of parents to stop having children after having the desired gender or genders. Parents in the US may have a "balance preference", a desire to have one of each gender. Here's what the data shows: Did the first child's gender influence whether to have a second child? Parents are slightly more likely to stop having children if the first child is a girl. First Child Parents Having 2nd Child Boy 70% Girl 68% Did previous children's gender influence whether to have a third child? Parents are 6% more likely to stop having children if the first two children are a boy and a girl. Of parents with two same-gender children, parents of two girls are 3% more likely to stop having children than parents of two boys. Previous Children Parents Having 3rd Child Boy/Boy 46% Boy/Girl 39% Girl/Girl 43% This table shows families with two same-gender children combined. Previous Children Parents Having 3rd Child Same Gender 45% Mixed Gender 39% What about the fourth child? Parents of 3 same-gender children are only 2% more likely to have a 4th child than parents with mixed-gender children. Parents of 2 boy, 1 girl families are the most likely to have a 4th child. Previous Children Parents Having 4th Child 3 Boys 29% 2 Boys, 1 Girl 35% 1 Boy, 2 Girls 20% 3 Girls 26% This table shows families with same-gender children compared to families with mixed-gender children. Previous Children Parents Having 4th Child Same Gender 28% Mixed Gender 26% Odds of Having a Boy or a Girl Okay, finally! Let's look at the odds of having a boy or a girl, given that previous children are all of the opposite gender. Odds of Having a Girl The odds of having a girl seem decrease after having each boy, but only very slightly. Even after 3 boys, you are only 6.4% more likely to have a 4th boy than a girl. Previous Children % Girl Births None 49% Girls 1 Boy 50% Girls 2 Boys 47.7% Girls 3 Boys 43.6% Girls Odds of Having a Boy The odds of having a boy seem to increase after having girls, except after 2 girls, when a 3rd girl is more likely. Previous Children % Boy Births None 51% Boys 1 Girl 54.5% Boys 2 Girls 46.0% Boys 3 Girls 52.7% Boys Gender and Birth Order Given the charts above, it looks like you are slightly more likely to have a boy, regardless of previous children. This is probably due to the overall 51/49 boy/girl birth ratio. This ratio, interestingly, varies slightly with birth order; it isn't consistent among first-borns, second-borns, etc. 1st Born 51.0% Boys 2nd Born 52.2% Boys 3rd Born 48.6% Boys 4th Born 50.8% Boys Odds of Having an All Same-Gender Family If there are roughly even odds of having a boy or a girl with each baby, given the laws of chance we should still expect to see some all same-gender families, even in large families. Here is the number of all same-gender families we would expect to see, purely by chance: Family Size Same-Gender Mixed-Gender 2 Children 50% 50% 3 Children 25% 75% 4 Children 12.5% 87.5% 5 Children 6% 94% 6 Children 3% 97% 7 Children 1.6% 98.4% Now let's take a look at how this compares with the actual data. 2-Children Families All Boys 25.8% Actual 25.0% Predicted Mixed 52.2% Actual 50.0% Predicted All Girls 22.0% Actual 25.0% Predicted 3-Children Families All Boys 14.9% Actual 12.5% Predicted Mixed 73.0% A 75.0% P All Girls 12.1% Actual 12.5% Predicted 4-Children Families All Boys 9.1% Actual 6.3% Predicted Mixed 85.4% A 87.4% P All Girls 5.5% Actual 6.3% Predicted Conclusion Although we often hear the "statistic" that you are 30% or even 70% more likely to keep having the same gender, this is just an old wives tale. It is NOT a fact. The truth is, your odds stay pretty close to 50% for each child and only vary slightly. If you have had 2 or 3 boys, you are only about 2% to 6% more likely to have another boy. If you have had girls, you are slightly more likely to have a boy next.   Source: https://www.in-gender.com/xyu/Odds/Gender_Odds.aspx

mommy5point0

Huh. Well this is interesting. It makes sense. I'm FINALLY having a 2nd boy after 3 girls and 1 boy.

CanukMam

Another possible reason for more male births. Some cultures in the US & Canada get early ultrasounds/tests to determine gender and abort the females. Sad but it's happening..

https://www.cbc.ca/news/canada/fetal-gender-testing-offered-at-private-clinics-1.1183673

A study released in April (2012??) in the Canadian Medical Association Journal confirmed previous research showing that the male-to-female ratio for third-born children to women born in India and living in Ontario is higher than the natural rate. 

mshepherd20

Thanks for posting. Those are pretty neat statistics!

britb618

That's terrible @CanukMam‌ although it is pretty normal to be able to do an elective test for the sex in America (for a price) I never thought people would use it for this purpose....really hope that's just a small segment of the population and that these women can be helped....so sad

Stargirlb

Most medical professionals here in BC will not tell you the sex routinely until after 20 weeks. I won't be able to find out until then. 

Maebb

There was a family in my church growing up with 4 girls. Whoa.

Someone has already asked me if we'll have a 3rd baby to "try for a girl" if this next one is another boy, but the thought of 3 boys is scary to me.

LaBellaVida

I saw on the news once a woman who kept having kids to try and have a girl. She had 12 boys. Lol. I think she said she'd keep going to get a daughter, but not sure.

I couldn't imagine 12 kids. Let alone all boys!

Eta: I think she team green too.

CanukMam

I'm still able to find out (in ontario) at my anatomy scan at just over 18 weeks. I was looking online for elective options to find out sooner (I'm impatient) and no where does it before 19-20 weeks. It's a shame that these folks ruin it for the rest of us!

Stargirlb

If we want to know sooner we can just get a private ultrasound, but I'm too spoiled by all my free healthcare, the thought of paying money for something is offensive to my socialist utopian senses. 

Jokes. Actually got a private one at 33 weeks the first time around. I had an ultrasound at 18 weeks, and my doctor refused to tell me the sex because he was extra strict and said only actual 20 week and later ultrasounds were *allowed* to tell me the results. So I asked when my next ultrasound would be, and he told me I did not need another one since the baby looked great and he wasn't convinced they were safe. I was 18 and it was my first baby so I just figured that's how all the docs did things and went ahead and booked myself a private ultrasound. My midwives booked my ultrasounds this time and last time for 18 weeks and they just could not give me the Sex envelope until 20 weeks. So turns out my doctor was just an Ultrasound Sex Vigilante. lol

Lanatir

Shettles has been disproved.  Unfortunately, this is the closest thing I can find right now to what I normally post for it.. Ugh.  I really need to book mark more...

https://www.fertilityfriend.com/Faqs/Gender-Selection-Methods---Scientific-Evidence.html

Interesting read, though.

longcat07

this was kind of neat to look at, but i'm still going with 50/50.  it's all within a reasonable margin of error.

interesting fact about my family: my mother is the second of four girls (no boys) and my bio dad is the middle of five boys (no girls).

Eyefrog

I still think its 50/50 either way. We did not keep having children going for the elusive girl, we wanted a large family and it still would have happened regardless if we had a girl or not. 

jmcmoe

Maebb said:

There was a family in my church growing up with 4 girls. Whoa.

Someone has already asked me if we'll have a 3rd baby to "try for a girl" if this next one is another boy, but the thought of 3 boys is scary to me.

I grew up with three sisters! there must be something in the water in our neighbourhood/farming community because there are several all girl families around us that have three or more girls including one family with 5 girls and one with 6! And we know several dairy farming families with four girls!

Beauxbaton

@jmcmoe‌ interesting. There is a theory that more dairy somehow makes you more likely to have a girl. I mean obviously don't put too much stock into that. But just the fact you said dairy farmers with lots of girls is interesting to me.

Kiisu2014

Pretty Interesting it would be our first child so regardless of what sex our child will be these coming January will still would make a second child

Twochickshavinachick

Interesting to see the stats laid out like this.

I remember reading somewhere a piece about increasing the odds of having a boy. They said that female sperm is hardier, copes better with alkaline environments and so can outwait male sperm for the egg to drop. So the longer sperm is waiting for ovulation, the higher the concentration of female sperm.  But if ovulation has just occurred and there is no waiting, the slightly faster male sperm has the advantage.  Using this logic, they suggest bd-ing/insem'ing the day of ovulation to increase the chances of a boy.

This is particularly interesting to us, since we worked out that the month we were successful, we had insem'd the day after ovulation.  We've found all the old wives tales of gender prediction fascinating and have included some of them with our guess-the-gender game that went out in the family newsletter.

spoonleg

Interesting. I read some twin statistics that said for twins (fraternal), the most common configuration is boy/girl, followed by girl/girl. Boy/boy twins are the least common. In identical twins, girls are also more common. The difference is marginal, but still of interest.

We have been told our twins are boys.

Beauxbaton

@spoonleg‌ that's interesting about twins. My great grandmother was an identical twin. My husbands grandfather is the boy in a boy/girl twins pair. And on my original BMB there is at least 2 sets of boy/girl twins. And a set of boy fraternal twins.

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