Men getting pregnant

I'm just a dumb hillbilly, so I'm having a bit of a difficult time with the concept of pregnant men. To be pregnant, one must have a uterus, the organ in which the developing fetus is located. Only people born with 2 X chromosomes have a uterus, but that doesn't mean they're women because in this age you can choose if you're a man or woman, and you can change back and forth if you wish, i.e. "gender fluid". Your chromosomes don't determine your sex, the organs you're born with don't determine sex, the ability to carry and deliver a child doesn't determine sex. Apparently your sex is whatever you say it is. So what exactly does it mean to be a man? If a person assigned female at birth, who has 2 ovaries, a uterus, and children he/she/it/they have delivered decides they are a man, what exactly does that mean? Apparently it means nothing. Conversely, if a person assigned male at birth who has a functioning penis and testicles and both X and Y chromosomes in every cell of their body gets convicted of rape, that person can declare they are a woman and they get to go to a woman's prison. There the person can get free room and board, health care, and more pussy than a coke dealer with a harley and a boat. By the way, "gender" is a term of grammar. The "gender" of "car" in spanish is masculine, el carro. The gender of table is feminine, la mesa. "Gender" used in place of "sex" to make is easier to talk about.