I am female and happily married, most of my good friends are male. I think that in any platonic relationship, one person has a crush on the other. It is the magnet in the relationship. As James says, there has to be a clear set of boundaries. One of my friends was a bad date, I realized there were no sparks, but intellectually we clicked. My husband calls him, his alternate as when my husband is busy and can not attend functions with me, this friend goes to scope out women LOL. Being friends with the opposite sex is very informative and a great insight. Just be careful that you are not fooling yourself into thinking that platonic is enough if you have more than just a slight crush on the other person. Doing this can cause you to stop looking for the right relationship and settling for just friends with the wrong one.