# Can you choose the sex of your unborn child? **URL:** \ **Category:** Factual Questions\ **Created:** [September 27, 2002, 12:03pm UTC](https://boards.straightdope.com/t/can-you-choose-the-sex-of-your-unborn-child/129858 "2002-09-27T12:03:59Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![AladyLikeNoOther](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@AladyLikeNoOther](https://boards.straightdope.com/u/AladyLikeNoOther)\ **Post date:** [September 27, 2002, 12:03pm UTC](https://boards.straightdope.com/t/can-you-choose-the-sex-of-your-unborn-child/129858/1 "2002-09-27T12:03:59Z")
I read a while back that you can choose the sex of your child by having sex in different postions and during different times of the month because the x carrying sperm is larger than the y carrying sperm, the entire basis for this theory. ??? ---
**Author:** ![Sebhal](https://avatars.discourse-cdn.com/v4/letter/s/47e85d/32.png) [@Sebhal](https://boards.straightdope.com/u/Sebhal)\ **Post date:** [September 27, 2002, 12:27pm UTC](https://boards.straightdope.com/t/can-you-choose-the-sex-of-your-unborn-child/129858/2 "2002-09-27T12:27:40Z")
This is something into which I’ve been doing some research of late, and as far as I can tell, as you’d expect, it isn’t possible for certain, but you can sway the odds. EXPLICIT BIT COMING UP! I think that the critical thing seems to be the acidity of the vagina. Thus conception pre-ovulation means more/ less acid and pushes the odds one way, post-ovulation the other. (Having said that, I’ve also read that it’s impossible to conceive with sex after ovulation). Along the same lines, ejaculation near the mouth of the vagina is likely to have a different result to deeper, because of the acidity. A woman’s orgasm also makes a difference. I know all of this is a bit wooly on the details, but I’ll nose around a bit and see if I can come up with cites. N. ---
**Author:** ![Shade](https://avatars.discourse-cdn.com/v4/letter/s/2bfe46/32.png) [@Shade](https://boards.straightdope.com/u/Shade)\ **Post date:** [September 27, 2002, 1:25pm UTC](https://boards.straightdope.com/t/can-you-choose-the-sex-of-your-unborn-child/129858/3 "2002-09-27T13:25:26Z")
I’m sure there was a Straight Dope column on this, but I can’t remember it. I think Cecil said that no-one had found a foolproof way, but you might as well try what **Nerrie** described, as it’s free. But I’m not sure. Woman 1: My husband was on top when my child was concieved, so it’s going to be a boy. W2: I was top - mine must be a girl. W3: OH NO! I’m going to have puppies! ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [September 27, 2002, 2:02pm UTC](https://boards.straightdope.com/t/can-you-choose-the-sex-of-your-unborn-child/129858/4 "2002-09-27T14:02:20Z")
IIRC there was a ‘scientific’ method for choosing the sex of your child but I think it was nowhere near foolproof and only really pushed the odds one way or the other and even very much I think. I may have the details wrong but I think the idea was to take the man’s sperm and essentially put it in a centrifuge. X sperm are somewhat different in weight than Y sperm so they would separate in the centrifuge. Pick the sex you want and grab the turkey baster (sorry…bad joke). ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [September 27, 2002, 2:20pm UTC](https://boards.straightdope.com/t/can-you-choose-the-sex-of-your-unborn-child/129858/5 "2002-09-27T14:20:33Z")
Oops…should be: "IIRC there was a ‘scientific’ method for choosing the sex of your child but I think it was nowhere near foolproof and only really pushed the odds one way or the other and **not** even very much I think. ---
**Author:** ![Thing\_1](https://avatars.discourse-cdn.com/v4/letter/t/ce73a5/32.png) [@Thing\_1](https://boards.straightdope.com/u/Thing_1)\ **Post date:** [September 27, 2002, 4:56pm UTC](https://boards.straightdope.com/t/can-you-choose-the-sex-of-your-unborn-child/129858/6 "2002-09-27T16:56:20Z")
> [@](#): > > Thus conception > pre-ovulation means That would be a feat. **Nerrie** , I think you mean coitus pre- or post-ovulation. Last I heard was pretty much what **Whack-a-Mole** wrote, although I recently heard a new theory. It proposes that sexually conservative women tend to have daughters while more adventurous women tend to have sons. Obviously this is hardly scientific, but it correlates with my observation of my wife’s mother having 4 daughters and my wife and I having 3 sons. Make of this what you will. John ---
**Author:** ![MMI](https://avatars.discourse-cdn.com/v4/letter/m/53a042/32.png) [@MMI](https://boards.straightdope.com/u/MMI)\ **Post date:** [September 27, 2002, 5:55pm UTC](https://boards.straightdope.com/t/can-you-choose-the-sex-of-your-unborn-child/129858/7 "2002-09-27T17:55:56Z")
IIRC from way back in Biology class in high school (many many moons ago), Aladylikenoother, you are substantially correct. If intercourse occurs near ovulation, the smaller, faster scrappier androsperm (Y) will tend to reach to ova first and thus there is a greater chance of a male child. If intercourse occurs before ovulation, the acidity will tend to kill off androsperm faster. while the larger, more robust gynosperm will still be around to fertilize the egg. I’m not sure what the magnitude of the difference is though.