Boys playing girls toys

I girl was complaining that her sister gave a Barbie to her son to play with . What's the big deal? Would I ever buy my son a girl you probably not but I can't say for sure. Just bc he's a boys boy . But if we are at a friends house and she has a girl I wouldn't care if he played with girl Toys. Or vice a verse if I had a girl. What's the big deal? I don't believe playing with opposite see toy is going to make anyone gay or confused .