You could never have mixed gender teams in ANY team sport. Well you could, but unless it was mandatory to have a percentage of women, they'd just all be men because men are faster, stronger and more powerful.
Are you serious? There is no argument to have: men ARE physically stronger than women, which is the reason why all men's athletics world records are in the region of 10-20% faster, higher, longer, heavier etc.
As for KLL versus Nicola Adams, this is comparing apples with oranges. KLL is a...
You need to be realistic and accept the physical differences between men and women. The difference in footballing ability will never diminish as long as athletic aspects, such as pace, are parts of the game - not to mention shot power and jumping ability.
Seriously? I can't think of any team sport where physical strength doesn't play a part.
The only sports I can think of off the top of my head where men and women compete equally are equestrian and motor racing.