Dear Prudence: Is penis size hereditary? Because my brother’s is quite different.

Help! My Brother’s Giant Genitals Make Me Doubt We Have the Same Father.

Help! My Brother’s Giant Genitals Make Me Doubt We Have the Same Father.

Advice on manners and morals.
May 16 2013 6:15 AM

Big Difference

I never doubted my brother and I had the same father—until I saw the size of his genitals.

Emily Yoffe.
Emily Yoffe

Photo by Teresa Castracane.

Get Dear Prudence delivered to your inbox each week; click here to sign up. Please send your questions for publication to (Questions may be edited.)

Got a burning question for Prudie? She'll be online at to chat with readers each Monday at noon. Submit your questions and comments here before or during the live discussion.

Dear Prudence will be taping a special wedding-themed podcast in early June. If you'd like to discuss your wedding-related problem directly with Prudie, send us your question by May 31 to Please put "Podcast" in the subject line and include your phone number.

Dear Prudence,
I am the middle of three boys and we are all in our 20s. Our parents separated shortly after my younger brother was born and eventually they went through a bitter divorce. Recently, my father, brothers, and I went to a camping-style family wedding together. The facilities were spartan and we all ended up in a communal shower. I'm sure this was the first time all four of us were naked together, and it was certainly the first time I'd seen my younger brother naked since he was little. In the shower, there was a definite "one of these things is not like the other" moment. While my older brother, dad, and myself have fairly similar, if modest, endowments, my younger brother's male parts were noticeably different (and "better") than ours in almost every way possible: size, shape, even complexion (!). It was like seeing a great white whale breaching alongside dolphins. None of us look strikingly like our parents, but we are clearly brothers, except for this newly discovered alien appendage on my younger brother. At the reception, my older brother brought this up to me immediately, and we worked out the theory that mom had an affair that gave rise to my baby brother, and his decidedly different genitalia, and the divorce. I don't think full brothers could have such variation, and the fact that my younger brother's package is a definite upgrade plays into the theory that maybe mom was shopping around for a better deal. We'd really like to get to the bottom of this, but we're not sure how to broach this already difficult topic with either parent when our only evidence consists of this sensitive observation.

—No Ahab


Dear No,
It’s the Johnson brothers, Willie, Peter, and Rod! You and your brother got quite an eyeful of baby bro’s one-eyed wonder. I wish I knew what you meant by the superior “complexion” of your brother’s endowment. I’m just supposing that his Moby-Dick gives off a rosy glow due to excess blood flow. There are several ways to approach your central question: Did your mother give your father the shaft? First of all, you seem to be of the opinion that sexual characteristics are inherited only from the parent of the same sex. But as this website points out, genital size, like eye color and height, are traits inherited from both parents. It’s perfectly possible that your mother comes from a family of three-legged men and you and your older brother got the short end of that genetic lottery. You have one ambiguous (though substantial) piece of evidence for your theory that your parents’ divorce was due to your mother’s infidelity. But maybe your mother discovered that while she was gestating your father’s third son, he was the one cheating on her. Despite the nastiness of your parents’ parting, they have kept the reason quiet all these years. Since all of you boys appear to have been happily incurious about their split these many years, it’s probably a good idea to remain that way. You want to establish that your baby brother isn’t really a member of the tribe. But pursuing your hunch will only make a cock-up of things because nothing can change the fact that your father has always embraced all of you as his three sons.


Dear Prudence Live in New York: Preschool Scam

Dear Prudence,
A while ago while searching for a book in my mother's office I came across her will, and though I know I shouldn't have looked, I did. I have been struggling with what I discovered ever since. My stepfather is slightly younger and significantly healthier than my mother, and if she dies before he does, he and my half sister—their child—are her sole beneficiaries. If my stepfather dies first, then my half sister will get half of my mother’s estate with the other half divided between my full brother and me. I’m married, financially stable, and have a successful career. I don't care about the money, but I can't shake my sadness about my mother's choice not to provide anything, not even of sentimental value, for my brother and me should she pass away before her husband. I adore my half sister (who is significantly younger than I am) and my stepfather and begrudge them nothing, but I find myself resenting my mother. I've always felt like her least favorite child, especially compared to my half sister. I don't want to be bitter toward my mother and I was hoping my sadness about this would go away, but it continues to fester and remind me of how she's never been as proud of or kind to me as to her other children. Should I bring it up with her to clear the air? Or should I just keep trying to get over it? I'm ashamed of having peeked at her will and I'm skeptical that a conversation with her about it would go over well.

—Eldest Daughter

Dear Eldest,
Good for you for not even being slightly tempted to suggest your stepfather attend the running of the bulls on his summer vacation, or take up BASE jumping as a hobby. I also admire your ability to separate your feelings about your mother from the objects of her affection—her husband and their daughter—and not take your perfectly understandable resentment out on them. Unless one child is absolutely rolling in dough, or another child has special needs, I don’t like beyond-the-grave social engineering and favor equal inheritance among siblings. Parents should remember that once they’re gone it’s always possible that the successful child suffers a health or financial reversal, while the lost soul ends up selling an app to Facebook. Siblings understand there is no such thing as absolute parental equality: What they are looking for is fairness. It’s a big failing for a parent to leave her children feeling inequitably loved, and a terrible parting gift to leave festering resentment. But I’m also going to suggest you consider the information you stealthily obtained in a different context. If may be that your mother is relieved, proud, and happy that you and your brother have done so well and are set. Perhaps what you see as greater attention to your half sister is largely a function of her being younger and less grounded. If your father has amassed an estate, perhaps your mother is also assuming that you and your brother will inherent substantially from him. And you don’t know if there are other documents suggesting her three children divide her memorabilia as they see fit. I agree with you that it will not go well to have a conversation with your mother about her will. But it’s perfectly legitimate if you want to talk to her about your lifelong sense of being less appreciated than your siblings. First bounce this off your husband or a good friend to strategize over what could come from disinterring such feelings.