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Here’s why, according to four of my friends.

"Everything I learned about girls, sexually, came from my guy friends. But everything that was actually true and helpful came from my female friends. Especially my older sister's friend, Alexa. I cannot count the times she took me aside, and was like, 'Do this. Don't do that'. My sister was always like, 'Let him figure it out'. Which I thought was mean, but I also kind of understand. Alexa told me to always make sure a girl comes first. In bed, that was the most important advice a friend ever gave me."

-- Michael, 21, student

Sidenote: Alexa told Michael that if he didn't have sex by the time he finished high school, she'd get with him so he wouldn't have to go to college a virgin. No judgment, but that's a pretty great friend

"My wife and I share a lot of friends. My wife is not the jealous type, but I have fewer female friends than I did before she and I were serious. For whatever reason, when you get with someone permanently, those relationships tend to dwindle. My female friends are great for helping me plan things (they know what restaurants she likes, or if she's been looking at a dress or something), and also for filling me in on stuff. I won't know something is happening with my wife, and one of her friends will ask, 'So, have you guys figured out if you want Xbox or Playstation?' And that's how I'll know my wife wants a video game system. Except I made up this example. This kind of thing happens, but more with paint colors and appliances, not so much video games. God I wish my wife would let me have Xbox. Maybe I'll get one of our friends to suggest it to her."

-- Arjun, 30, insurance

"My best friend is a doctor. She tells me to stop whining whenever I think I'm dying because I have a cold. She also gets me penicillin whenever I am actually sick (she once bought me an enema as a joke). Other than that very practical example, I can't say that she provides any more or less wisdom than my guy friends. She's smarter than most of my other friends; I'll say that."

-- Sean, 26, banker

"Women hold all the secrets (to life, maybe to the universe as well). Off the top of my head I can think of the following: Always let a woman know who's in charge in the bedroom; never make reference to a woman's time of the month; always say you will eat some dessert at a restaurant, even if you are full; tell a woman you hate smoking instead of making that weird face after you kiss; people don't get funny. That last one was by far the most important. It came from my friend Hally. She's completely hilarious."

-- Terrence, 25, bartender/guitarist