Do Male Mammals Ever Lactate

From Jared Diamond’s Why is Sex Fun

Chapter 3- Why Don’t Men Breast-feed Their Babies?

If a developing embryo has a Y chromosome the bipotential gonad develops into a testicle in the 7th week. If no Y chromosome is present the gonad becomes an ovary in the 13th week. A female is produced if there is only one Y chromosome, and a male is produced if there is one Y and two X chromosomes. A woman is the default condition.
If a testicle is present it will produce testosterone, which gets converted into dihydrotestosterone. These androgens convert some all-purpose embryonic structures into the glans penis, penis shaft, and scrotum. These same structures would otherwise develop into the clitoris, labia minora, and labia majora. Embryos start out with two sets of ducts, the Mullerian and Wolffian. In the absence of testes the Wolffian ducts atrophy, and Mullarian ducts develop into a uterus, fallopian tubes, and interior vagina. If testes are present, the Mullerian ducts atrophy and the Wolffian ducts develop into the seminal vesicles, vas deferens, and epididymis.

There are a number of different sorts of male pseudohermaphrodies. One type lacks the cell receptor, which binds testosterone and dihydrotestosterone, and develops into a normal looking, and frequently quite attractive appearing “female”.

Sexual dimorphism varies quite a lot between species. In some species males and females are very much alike, in others quite different.

Human females who are not pregnant and even virgins sometimes lactate, and men have been known to lactate after starvation or when hormones are administered. Lactation has been described in male goats and in male fruit bats.

Diamond thinks that men don’t lactate because of “evolutionary commitment”, that is it is difficult for an organism to change after millions of years of doing things the same way. He seems to suggest that male lactation could evolve sometime in the future for human males.

Hi Randy Weaver, and welcome to the Straight Dope!

First thing I’m going to do for you is to make a link to Cecil’s article on male nipples, which I’m guessing is what brought you here: Why do men have nipples?

The general answer to your question is yes. Several male mammals, including some bats and at least one human have been known to lactate without hormonal assistance!

I’m also going to link to a bunch of previous threads where we’ve talked about this, because there’s been lots of interesting discussion on the topic, but I know guests can’t search to find old threads.

(Nah, I’m not really being nice, this is the “first one is free” to get you hooked on the Dope so you become a Member! :wink: )

One thing I’ll warn you about, though, is it’s considered bad form to post a reply to a thread that’s been dormant for three months or more, so if you find anything that you want to reply to, you’re best off summarizing the point or linking to the old thread and replying here. Frustrating, I know. But sometimes these old threads have posts by people who aren’t around any longer and “Zombie threads,” as we like to call them, are (for reasons I don’t fully understand) a no-no.

Male lactation…any stories?
SD Classic: re Male Nipples

Male lactation

Male lactation

Can men lactate?

Is Male Breast Milk As Nutritious As Female Breast Milk?
Male Lactation

Beg pardon? It was my understanding that the typical complement of sex chromosones was 1 X and 1 Y for a male or 2 X for a female, that at least one X was necessary for survival past the few-cells stage, and that the presence of any Y resulted in a male.

I rather fancy the first “Y” quoted was meant to be an X. Otherwise, the subsequent statement

makes no sense.

Well, the statement woman is the default condition makes no sense, no matter what the surrounding context is.

In fact, we recently beat this notion out of Kimera’s head in this thread.

There’s a difference between “is wrong” and “makes no sense”.

Thus: Men who lactate need comply with the Mutant Registration Act! :eek: :eek: :eek: