Gendered Curling

Does anyone know why curling competitions are divided into men’s and women’s games?

Perhaps there is an obvious answer, but I cannot work it out.

Possible answers that I’ve considered so far include the following:

• Men might generally be able to throw the stones with more force.
• Perhaps men and women use different sized stones.
• One sex has the advantage over the other when it comes to brushwork.
• St Paul said it should be so.

Further suggestions are most welcome.