Why Men Fall Asleep After Sex, and Other Answers

Co-authors Mark Leyner and Dr. Billy Goldberg give answers to questions ranging from the bizarre to the slightly embarrassing in "Why Do Men Fall Asleep After Sex," their follow-up book to their No. 1 New York Times bestseller, "Why Do Men Have Nipples?"

From questions about dogs' belly buttons to knocking down old wives' tales -- no question is too weird for this duo.

The authors answer a few of those important medical questions below.

"Why Do Man Fall Asleep After Sex" is available in bookstores now.

Question: So you put it out there -- and we've got to ask: Why do men fall asleep after sex?

Leyner: People have no idea how much work it is for a man to produce an ejaculation. You have this seminal vesicle churning out this fluid, the prostate gland producing an alkaline solution. It's like having five iron chefs in your crotch working to cook up this stuff.

Goldberg: There are hormones that are secreted at orgasm -- proloactin, oxytocin --that facilitate sleep. But you have to accept as gospel that men orgasm more than women. If that's true, then you have your answer as to why men fall asleep after sex. ...And it seems like women don't. If women orgasm as much as men, we might all be asleep all the time.

Question: Who snores more -- men or women -- and why?

Leyner: Men snore more and a lot of it is anatomic. Men's airways aren't as wide as women's and when men gain weight they gain it around their neck which constricts the airways. Women, on the other hand, gain weight in their hips.

Question: Who listens more -- and why?

Leyner: There are some physiological reasons behind the cultural stereotype.

Goldberg: It's not that we listen less -- it's that we listen differently. A couple of studies used MRIs to look at men versus women, and what happens inside their brains while they're listening. Men use one side of their brain whereas women use both sides. And when men hear women's voices they hear those voices in different areas of the brain than women -- they hear women's voices in the same area of the brain they use to process complex musical sounds -- so you can extrapolate the women's voices are more complex. ...And more difficult for us to listen to. Question: An apple a day keeps the doctor away: Fact or fiction?

Leyner: Fact-ish...

Goldberg: Apples are good for you -- there are antioxidants and fiber especially in the skin just like you'd find in red wine. … So it does have improved health benefits. So, yes, you can make that leap: an apple a day.

Question: Does barbequing cause cancer?

Leyner: This is a bit of a buzz kill, especially during summertime. But yes there is some evidence of the dangers at the barbeque. Barbequing creates two compounds --one on the surface of the meat when you char it and the other that's created at high temperatures of cooking and that can contain carcinogens.

Goldberg: The solution is cook your meats slowly, marinate it and scrape off the charred parts.

Leyner: And look at it this way, now when dad -- the greatest dad in the world -- puts on that apron and heads to the barbeque, he's also risking his life to bring you a great burger.

Question: Is green tea really good for you?

Goldberg: Look we're all searching for this magic elixir that will save us -- there are some compounds in green tea that are good for you. But these are in trace amounts for the most part. It's not a silver bullet.

Leyner: We prefer mountain dew. It's highly caffeinated, tastes better and looks like anti-freeze.

Question: Why do some people sweat excessively?

Goldberg: There's a condition called hyper hydrosis. Basically these people are heavy sweaters. They can sweat from their face, palms, almost anywhere. There are medical treatments for it -- antiperspirants....even surgery.

Leyner: And then, you can do as the models do and get botox in the armpits. That stops the sweating.

Question: Do dogs have belly buttons?

Leyner: You would never know it, but yes. You can spend hours flipping your dog over and never find it.

Goldberg: We recommend flipping them over on a rainy day and finding it. People's expectations are that belly buttons comes from neat little knots tied by a doctor. They figure dogs can't do that with their paws. But it's not true -- the stump falls off, it heals and there's the belly button. Question: Is a dog's mouth clean?

Goldberg: I took this one personally because my dad always told me -- and I took as the gospel truth -- that one day everyone would have a helicopter of their own and that dog's mouths are perfectly clean. And that's absolutely not true.

Leyner: Actually what's worse than a dog's mouth is a cat's mouth. They're not dirtier per se, but they have sharper teeth, so they are much more likely to go deep, should they bite you.

Question: Why don't mosquito bites hurt when you get them, and why do they itch?

Goldberg: Mosquitoes are fiendishly advanced technological creatures. When they bite you, they inject a number of things. First of all, only the female bites and she's not "biting" so much as "drinking" your blood. And she does two things -- she injects an anti-coagulant so she can drink up the blood easily without those clots. And she injects a little anesthetic so you don't feel it. Obviously if you felt the bite while it was happening you'd smack the mosquito so the system is ingenious.

Question: Why are some people sweeter to mosquitoes?

Leyner: It's not anything in a particular person. Mosquitoes are attracted to things you can't avoid: body heat, carbon dioxide from exhalation. If you have no body heat and no exhalation you're dead. They're attracted to sunblock, perfume even sweat.

Question: Why do you have a bionic sense of smell when you're pregnant?

Goldberg: I'd walk home from work and my pregnant wife would make me stand outside with the trash because she thought I smelled badly. Why do they smell so well? It's the hormones. Hormones increase your sense of smell so you can avoid toxins.

Leyner: It's understandable. Heightened senses mean a heightened awareness of what's not good for your unborn baby.

Question: Are more twins conceived in the summer than any other time of the year?

Leyner: There's a small increase in twins conceived in the summer but one possible reason for it -- some believe is the hormone, the follicle stimulating hormone that makes conceiving twins more likely and that hormone is at its highest levels in the summer.

Question: When you pull out a gray hair, do two come back in its place?

Leyner: No, absolutely not. There are so many wives' tales out there and this is one of them.

Goldberg: If you pull out or shave a hair, another hair is going to come back in a prescribed period of time and it will grow back the same color as the first one. You're not going to make two hairs from one. If that were true, middle aged men all over the world would be frantically plucking their hair to get more hair to come in and fill in their bald spots.