Anyone else surprised at differences in gender after having children?

I asked this question before, and it got deleted. No idea why. Before I had children, I often umed that the differences in genders were mainly influenced by the parents and society. (buying boy toys for boys, playing rougher etc.) After having children, I was surprised at how much the differences seem to be innate. My son loves trucks and cars, long before we started buying them and he plays aggressively sometimes which I have never encouraged. He's home with me all day, so I try to get him to do other stuff like puzzles, books, and quieter games which he will do, but only for a short time and then he's back to smashing cars. Any else surprised by this?