Parents who have kids with the opposite sex, do you give them separate toys according to their gender or do they share toys?

I agree with Yuna. Sharing is fine because at the end of the day, kids are kids so let them play freely. When I was a kid, I even share the same toys with my cousins (who are boys) and so did my sister. I remember my Mikel, my cousin, used to play my sister's dolls as well.