There are certainly some things in behavior that are the result of chemical interactions in the brain. One of the most fascinating things I ever heard was a radio interview with a female-to-male transsexual, who described the impact testosterone therapy had on his brain: he'd be sitting on the subway and he'd see some random guy and be consumed with thoughts of wanting to beat him up. He hadn't had a lifetime of learning to control those impulses, so it was an unexpected and difficult situation for him to have to handle, and hearing him describe the "rush" in his mind was fascinating.
But sociologically we're a lot more complex than our brain chemistry, I change my own oil, set my own points (I have an old car), grease my own tie rods, and fix my own differential. I also sew my own clothes, cook my own food, and nurture my own kids. There is nothing "gendered" about any of this behavior other than the gendering that society gives it. The idea of a strict line between "masculine" and "feminine" is one of the myths that caused me to get wise to the WTS.