Should Mixed Teams be allowed to play in the Rugby World Cup?

I personally think that boys and girls should not be allowed to play in mixed teams in the rugby world cup, here are my reasons why.

Boys are built bigger than girls with more muscle mass so they are naturally stronger than girls. So i think boys would be more likely to run faster and would get more tries then girls would. This would make the game unfair as boys may feel they are better than girls because they score more tries. 

 Boys are more aggressive i've seen boys rugby games and girls rugby games and the boys rugby games always seem to have more fights because the boys get more angry and girls could get really hurt if they happen to get stuck in between a fight or accidentally get hit from a male during a fight.