A lot of structural hierarchies of social and economic structures are maintained by the utilisation of men as the mob enforcers of that hierarchy by moral religion or monetary control.

How ever men equal opportunity attraction to women creates the vehicle for greater social mobility and opening up of these structures as well

Relationships men form while in other nations, across social lines, cultural lines and race allows for greater cross cultural exchange and racial intermixing and tolerance.

Without it it would have been harder to break down those barriers.