male vs female strength

blackbeard

what is the expected strength differential between a male and female of equal size (ie roughly similar, height weight and build), assuming that both led equally sedentary lives.

i was told that a female is about 60% as strong as a male in the upper body and abouit 80% as strong in the lower body.

i assume that part of the reason is because

1)a typical male has half as much body fat as a female and hence at the same size carries more muscle overall than a female

2) a male has reltively bigger arms and is more muscular in the upper body than a female while a female has relatively heavier legs than a male and hence has relatively bulkier leg muscles

3) male muscles are naturally stronger than female muscles at the same size. (this is the bit that is most intriguing to me. while i have always assumed that male muscles are naturally stronger than female, i have come across quite a few people who have disputed this view, stating that the difference is only marginal at best and that male and female muscles are equally strong) - and this is proven by for eg female olympic swimmers swim faster than males from only a few decades ago; the same is true for other disciplines like sprinting (if you compare that typical female athlete of today she would be be out 6' and roughly the same size and weight as a male athlete from the 60s ie one generation ago.

what do people think?