Lol I meant it more in a "you're smart enough to stop leaving the milk out of the fridge, child!" kind of way. I agree sexism is still rampant, and I guess I'm implicitly saying people in the past are somehow excused because they weren't as intelligent, but what I'm intending to saying is that we're smart enough now, so we have no excuse.

one gender is predisposed to be bigger, stronger, have more testosterone, and has the ability to be stronger/build muscle more easily

I see this as a heuristic at best, and an excuse for sexism at worst. In my example above I'm specifically referring to two people who are equally physically capable of doing a task by definition. The man shouldn't be given preference simply because he's a man, and men happen to be stronger on average. That's not relevant when picking someone who can do the job.