Based on personal experience, men and women can be friends.

Personally, my roommate is female, and a friend. We're comfortable enough with each other to chill on her bed with no sexual overtones, hell we've fallen asleep on the same bed a few times.

My best friend is female. In her case, I am attracted to her, but since I know it won't ever lead to anything, I haven't done anything to persue her. Idk how that will end if it does.

My other really good friend from high school is female. We've kept touch over the years. She and I often have long lunches to talk about any and everything. It's an amazing way to get a perspective from a different gender. I can say with no doubt that there is nothing sexual between us.

So, to iterate what I said earlier, yes, yes men and women can be friends and just friends. It might be harder with specific people, but it can work if you and the other person just click, and not in a sexual/romantic way.