Absolutely they can! I've had almost exclusively male friends my entire life, and I wouldn't have had it any other way. I just get along so much better with men and have more in common with them. Admittedly, it is much harder to have female-male friendships once you're in a committed relationship, especially marriage, as jealousy can arise and sometimes, just for the sake of trust and avoiding temptation, it can be best to cut those ties. However, I am a married lady, and while I've made it kind of a "rule" that I don't hang out with my male friends alone, one on one, I still have a lot of male friends. We text, email, hang out in groups on occasion, and it's great. I love my boys, as I call them, and I wouldn't trade them for ladies just because it would be "easier" or less "taboo" or some such nonsense. The only thing I could say is be prepared that women can be... okay, this is a generalization and not true of all women, but most women can be jealous. Especially if you're very attractive or the women you're friends with are very attractive. So if you plan to have a real relationship in the future, be prepared that your new lady friend might not be too excited about your spending time with your other female friends as much as you were used to when you were single. But if you can handle that with class and learn that delicate balance, then I think opposite-sex friendships can be very enriching.