# Sexual Characteristics **URL:** \ **Category:** Factual Questions\ **Created:** [October 8, 2001, 1:47am UTC](https://boards.straightdope.com/t/sexual-characteristics/86024 "2001-10-08T01:47:01Z")\ **Posts on this page:** 19\ **Page:** 1
**Author:** ![Infidel](https://avatars.discourse-cdn.com/v4/letter/i/839c29/32.png) [@Infidel](https://boards.straightdope.com/u/Infidel)\ **Post date:** [October 8, 2001, 1:47am UTC](https://boards.straightdope.com/t/sexual-characteristics/86024/1 "2001-10-08T01:47:01Z")
Are sexual characteristics inherited from both parents, or merely the parent who the offspring shares the same sex with? What I’m saying is, lets suppose the fathers family is full of big titted women. The mothers family is full of small titted women. Will the female offspring of this union carry the breast characteristics of the father or the mother ? Or will the offspring carry the genes of both the father and the mother? Or, lets say the father comes from a family of small penis sized males. the mother comes from a family of large penis size males. Would the male offspring of such a union reflect only the fathers penis size? Or would he be somewhere between the father and the mother? ---
**Author:** ![ultrafilter](https://avatars.discourse-cdn.com/v4/letter/u/3d9bf3/32.png) [@ultrafilter](https://boards.straightdope.com/u/ultrafilter)\ **Post date:** [October 8, 2001, 1:53am UTC](https://boards.straightdope.com/t/sexual-characteristics/86024/2 "2001-10-08T01:53:10Z")
It depends on whether the trait is linked to the X or Y chromosome (or both). If the trait is linked to the Y chromosome, it’s solely determined by the father. If the trait is linked to the X chromosome, it depends whether the person is male or female. If they’re male, it’s solely determined by the mother. If they’re female, it’s determined by both parents. Otherwise, inheritance is more complicated. I’m not sure that traits like breast and penis size are entirely genetic, though; nutrition probably has a lot to do with it. ---
**Author:** ![heptapod](https://avatars.discourse-cdn.com/v4/letter/h/a88e4f/32.png) [@heptapod](https://boards.straightdope.com/u/heptapod)\ **Post date:** [October 8, 2001, 1:55am UTC](https://boards.straightdope.com/t/sexual-characteristics/86024/3 "2001-10-08T01:55:39Z")
Nutrition for penis size? Where would you infer this? Do you have any links? How dare you withhold such important information!!! Is there any veracity to the assertation that women’s bust sizes have been increasing due to the increase in hormones used in meat production? It sounds a little too wacky to be true. Then again, I’ve never seen a chesty vegan. ---
**Author:** ![ultrafilter](https://avatars.discourse-cdn.com/v4/letter/u/3d9bf3/32.png) [@ultrafilter](https://boards.straightdope.com/u/ultrafilter)\ **Post date:** [October 8, 2001, 2:02am UTC](https://boards.straightdope.com/t/sexual-characteristics/86024/4 "2001-10-08T02:02:55Z")
> [@](#): > > \*Originally posted by heptapod \* > **Nutrition for penis size? Where would you infer this? Do you have any links? How dare you withhold such important information!!!** That would be nutrition during childhood and adolescence, and it’s just a semi-educated guess. In general, the sizes of various body parts is heavily influenced by the quality of an organism’s diet. > [@](#): > > \*\*Is there any veracity to the assertation that women’s bust sizes have been increasing due to the increase in hormones used in meat production? It sounds a little too wacky to be true. Then again, I’ve never seen a chesty vegan. \*\* I’ve never heard anything like that. Breasts are mostly fat. If I had to guess, I’d say the reason that you’ve never seen a chesty vegan is that they tend to have relatively low-fat diets. ---
**Author:** ![Tuckerfan](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@Tuckerfan](https://boards.straightdope.com/u/Tuckerfan)\ **Post date:** [October 8, 2001, 2:50am UTC](https://boards.straightdope.com/t/sexual-characteristics/86024/5 "2001-10-08T02:50:02Z")
> [@](#): > > I’ve never heard anything like that. Breasts are mostly fat. If I had to guess, I’d say the reason that you’ve never seen a chesty vegan is that they tend to have relatively low-fat diets. I have! 😃 Dated her for six months and I can assure you that her vegan diet did **not** stunt the growth her breasts in any way! (Damn, I miss her, and not because of her breasts, either, though they were fun to play with! 😃 ) ---
**Author:** ![vandal](https://avatars.discourse-cdn.com/v4/letter/v/858c86/32.png) [@vandal](https://boards.straightdope.com/u/vandal)\ **Post date:** [October 8, 2001, 6:07am UTC](https://boards.straightdope.com/t/sexual-characteristics/86024/6 "2001-10-08T06:07:47Z")
> [@](#): > > \*Originally posted by heptapod \* > \*\*Then again, I’ve never seen a chesty vegan. \*\* This is probably because vegans weren’t always vegans. They choose to become vegans after puberty has ran its course. ---
**Author:** ![vandal](https://avatars.discourse-cdn.com/v4/letter/v/858c86/32.png) [@vandal](https://boards.straightdope.com/u/vandal)\ **Post date:** [October 8, 2001, 6:12am UTC](https://boards.straightdope.com/t/sexual-characteristics/86024/7 "2001-10-08T06:12:21Z")
(Note to self – do not post when tipsy.( Wrong quote. Meant to quote **Tuckerfan**. ---
**Author:** ![Fern\_Forest](https://avatars.discourse-cdn.com/v4/letter/f/71c47a/32.png) [@Fern\_Forest](https://boards.straightdope.com/u/Fern_Forest)\ **Post date:** [October 8, 2001, 7:35am UTC](https://boards.straightdope.com/t/sexual-characteristics/86024/8 "2001-10-08T07:35:13Z")
> [@](#): > > \*Originally posted by heptapod \* > **Nutrition for penis size? Where would you infer this? Do you have any links? How dare you withhold such important information!!!** Dad: “You better eat your greens son if you want to grow up and have a big penis.” There must have been a study about this out there somewhere. I’d wager breast size mostly comes from the mother and penis size mostly from father. But that’s just a guess. I’m a little to google as what I may find might not be pleasant. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [October 8, 2001, 9:00am UTC](https://boards.straightdope.com/t/sexual-characteristics/86024/9 "2001-10-08T09:00:36Z")
> [@](#): > > \*Originally posted by Osiris \* > **I’d wager breast size mostly comes from the mother and penis size mostly from father. But that’s just a guess.** this must be true; I’ve got much smaller breasts than my mother, and my penis is bigger than hers too. ---
**Author:** ![Fern\_Forest](https://avatars.discourse-cdn.com/v4/letter/f/71c47a/32.png) [@Fern\_Forest](https://boards.straightdope.com/u/Fern_Forest)\ **Post date:** [October 8, 2001, 9:26am UTC](https://boards.straightdope.com/t/sexual-characteristics/86024/10 "2001-10-08T09:26:44Z")
You see, the answer is out there. Now if only I could recall what George Costanza figured out about bust size… p.s. I meant to say I’m a little **afraid** to google for research in this area. ---
**Author:** ![11811](https://avatars.discourse-cdn.com/v4/letter/1/9d8465/32.png) [@11811](https://boards.straightdope.com/u/11811)\ **Post date:** [October 8, 2001, 1:50pm UTC](https://boards.straightdope.com/t/sexual-characteristics/86024/11 "2001-10-08T13:50:42Z")
…so then the Chesty Vegans is not a band? ---
**Author:** ![jmonster](https://avatars.discourse-cdn.com/v4/letter/j/dbc845/32.png) [@jmonster](https://boards.straightdope.com/u/jmonster)\ **Post date:** [October 8, 2001, 3:59pm UTC](https://boards.straightdope.com/t/sexual-characteristics/86024/12 "2001-10-08T15:59:12Z")
I think it was Dawkins that had an interesting theory about this. If your mom has large breasts, it probably means that your father **likes** large breasts, which means that his mother probably has large breasts and his father also likes large breasts. The same is true of your mom’s family. That means that you (I’m assuming you’re male) will have genes for liking large breasts all over your chromosomes and your sisters will have genes for having large breasts all over theirs. You’ll then marry a girl with large breasts, and your children will carry on the tradition. ---
**Author:** ![Tuckerfan](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@Tuckerfan](https://boards.straightdope.com/u/Tuckerfan)\ **Post date:** [October 9, 2001, 5:05am UTC](https://boards.straightdope.com/t/sexual-characteristics/86024/13 "2001-10-09T05:05:38Z")
> [@](#): > > This is probably because vegans weren’t always vegans. They choose to become vegans after puberty has ran its course. Dunno. She told me when she became one, but I don’t remember how old she was. Do know that when I met her she was at the tail end of puberty (she’d just turned 18). Have to shoot Dawkins theory down. My mom has small breasts, and while I’m not really a “breast man,” I do like large ones, though I don’t get to play with them often. ☹ ---
**Author:** ![jmonster](https://avatars.discourse-cdn.com/v4/letter/j/dbc845/32.png) [@jmonster](https://boards.straightdope.com/u/jmonster)\ **Post date:** [October 9, 2001, 5:23am UTC](https://boards.straightdope.com/t/sexual-characteristics/86024/14 "2001-10-09T05:23:26Z")
> [@](#): > > \*Originally posted by Tuckerfan \* > Have to shoot Dawkins theory down. My mom has small breasts, and while I’m not really a “breast man,” I do like large ones, though I don’t get to play with them often. ☹ To be fair, he was actually just trying to come up with a plausible hypothesis of why certain animals have runaway crazy-ass features, like peacock feathers. Us people have a different sort of mating strategy; I like breasts more than most guys, but I still value love over breasts. ---
**Author:** ![heptapod](https://avatars.discourse-cdn.com/v4/letter/h/a88e4f/32.png) [@heptapod](https://boards.straightdope.com/u/heptapod)\ **Post date:** [October 9, 2001, 5:29am UTC](https://boards.straightdope.com/t/sexual-characteristics/86024/15 "2001-10-09T05:29:12Z")
Hell, if it was true that eating one’s greens would get me a better chance at having a larger penis I know I wouldn’t have complained about eating them. ---
**Author:** ![Cyn](https://avatars.discourse-cdn.com/v4/letter/c/a88e4f/32.png) [@Cyn](https://boards.straightdope.com/u/Cyn)\ **Post date:** [October 9, 2001, 5:44am UTC](https://boards.straightdope.com/t/sexual-characteristics/86024/16 "2001-10-09T05:44:45Z")
I am the image of my father’s mother. 5’8", curvy with C cups, dark brown eyes, fair skin and curly hair. So I would say sex characteristics can come from either parents’ DNA. My older sister is 5’ nothing, hippy with B cups, dark skinned and has straight black hair. Just like Mamma. ---
**Author:** ![Cartooniverse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cartooniverse/32/3084_2.png) [@Cartooniverse](https://boards.straightdope.com/u/Cartooniverse)\ **Post date:** [October 9, 2001, 12:22pm UTC](https://boards.straightdope.com/t/sexual-characteristics/86024/17 "2001-10-09T12:22:23Z")
> [@](#): > > \*Originally posted by Mangetout \* > \*\* this must be true; I’ve got much smaller breasts than my mother, and my penis is bigger than hers too. \*\* ’ Exactly why we love you !!! 😃 😃 😃 Cartooniverse ---
**Author:** ![John\_Kentzel-Griffin](https://avatars.discourse-cdn.com/v4/letter/j/ccd318/32.png) [@John\_Kentzel-Griffin](https://boards.straightdope.com/u/John_Kentzel-Griffin)\ **Post date:** [October 9, 2001, 1:29pm UTC](https://boards.straightdope.com/t/sexual-characteristics/86024/18 "2001-10-09T13:29:43Z")
> [@](#): > > \*Originally posted by \*\*\*jmonster \*\* > I like breasts more than most guys, but I still value love over breasts. Not me! I like most guys more than breasts. ---
**Author:** ![mnemosyne](https://avatars.discourse-cdn.com/v4/letter/m/c4cdca/32.png) [@mnemosyne](https://boards.straightdope.com/u/mnemosyne)\ **Post date:** [October 9, 2001, 10:16pm UTC](https://boards.straightdope.com/t/sexual-characteristics/86024/19 "2001-10-09T22:16:21Z")
In an attempt to answer this question honestly, I would say that breast and penis size have variable heritability, meaning that the “amount” of the phenotype offspring will have will vary, even with the same parents. The amount of heritability is very high for some things, and very low for others. Now that I’ve just found my genetics textbook: Heritability is the porportion of a population’s phenotypic variance that is attributable to genetic differences. (Snustad, Simmons, Principles of Genetics 2nd ed.) Envirnmental factors and genetic factors are both reflected in the heritability values. The value of heritability may also differ among populations, due to different genes and different environmental effects. So back to what I was saying, its high for some traits, low for others.To give a couple of examples: Stature in humans: 0.65 Milk yeild in dairy cattle: 0.35 Litter size in pigs: 0.05 Egg production in poultry: 0.10 Tail length in mice: 0.40 Body size in Drosophila: 0.40 There are a couple types of calculations one can do to predict the phenotype of the offspring, which I don’t feel like going into, but just by looking at the above values, one can see that if you’re a human, your stature will resemble that of (both)your parents quite a bit (ie., somewhere in between). If you’re a pig, the number of babies you’ll have at one time has not much at all to do with that of you mother or grandmother, etc. So, back to the OP, assuming that penis and breast size are not x/y linked and that that doesnt come into play (I’m thinking there are probably many genes involved), then variable haritability kicks in, and doesn’t necessarily mean that small-breasted women will have small-breasted daughters, and large-penised men will have large-penised sons, and vice versa. Does that make any sense? Now back to the jokes…