I know a lot of girls who are stronger than a lot of guys I know, but that doesn't mean it's sexist to say that in general, guys are stronger than girls. Likewise, I also know a lot of girls who don't spend much at all and don't care to go shopping for clothes and I know the odd guy (not many, mind you) that like to go shopping... but that doesn't mean that in general, girls like shopping more than guys do.