I have conversations fairly often on this topic and I always give them the synopsis of my own research (the Shettles method, adjusting the woman's pH balance, positions to use during intercourse, etc.) then end with, "It's probably just a 50/50 chance no matter what."
That goes for families with two or three of the same gender, too!
Turns out that I was probably right.
This is one of the more interesting studies I have seen about this topic from:
Some tidbits from the research:
- The odds of having a girl seem to 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.
- The odds of having a boy seem to increase after having girls, except after 2 girls, when a 3rd girl is more likely.
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.
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.
ABOUT THAT GIRL
For me, this means that, yes, there is a slightly (VERY slightly) higher chance of us having another boy this time around (just like ANY time around!)...but there IS a 73-75% chance that we will have a girl in our three-child mix! :)