an independent comment:
1 mile = 1 mile.
i remember coming upon this in interviews at least three times so far with some successful (that is, olympic success) coaches and athletes. when it comes to workouts, at least, whether your a guy or a girl, all athletes are running the same % of race distance at the same % of race pace. if you're a guy running 10 miles at a marathon pace, your training group partner who's a girl, runs 10 miles at marathon pace, too. if you're running repeat 1000s at 5k race pace, ... etc.
if you're just running miles for the sake of running miles, then i don't know what the conversion would be. but if you're running miles for the sake of a particular workout and training emphasis, then they're the same for guy or girl.
here's an experiment: stop counting your miles per week. stop counting your miles per training cycle. simply put, stop counting miles. then wonder if you'd ask the same question. if every time you run there's a purpose, then a lot or most of your runs are going to be focused on running a certain pace for a certain distance, both of which are related to a race (pace and distance). girls race 10ks. guys race 10ks.
i bet that if you round up 100 random college guys and 10 college female track team members, you're going to find a fair amount of college guys who, even with training, won't approach the same 800, mile, 5k, and 10k times as the girls. that is, there are guys who just aren't as genetically gifted -- on an absolute not relative level -- as these girls. when they're decently fit -- that is, when they ARE fit -- and still running slower than these girls, i'd give them the same workouts as their faster male counterparts ... AND their faster (and slower) FIT female counterparts.
just one take. and i certainly can waffle. ;)