The Logistics Behind Hagrid's Conception
Back in high school, I worked for the Deans' Office. Kids in detention or suspended were required to work quietly in a room off to the side, but the door was kept wide open so the deans could peek in and make sure they were behaving. At one point I started a discussion about how Hagrid was conceived, during which one of the students stepped out to tell me and my fellow workers, "You guys are fucking sick, you know that?"
Years later it still bothers me. Let's look at the evidence, shall we? Hagrid's father is a regular human, so we'll say he's about 5'10" (maybe even shorter because he could sit on Hagrid's shoulder when Hagrid was about seven feet tall). Hermione says in Goblet of Fire chapter 24 that giants are about twenty feet tall. When I read that sentence, I thought, "...Then how big is her vagina then?" If you're dealing with someone three times your height, how big is that thing? Will his penis get lost in there? Does it go up to his waist? Would she even derive pleasure from that encounter?
And then there's the actual impregnation. The average male ejaculates approximately 3.4ml of semen. Could that stuff even survive in the matrix of a giantess' vagina? Would it be able to make the trip? I'm assuming the Fallopian tubes are ridiculous in comparison to a human female's. Are giant sperm cells larger than human's to compensate?
So yes, when I read books this is the shit I think about.