Trigger Warning: I will be talking about biological sex, not gender so get your Tumblr crap out of here.

Now that I got that out of the way, I'm here to teach you guys about Sex Differentiation and X Inactivation. You guys probably know my relationship with Luis and how I'm constantly Rule 63ing him. I think I figured out a way to actually turn him into a girl (biologically) while somehow still having his XY chromosomes with these weird tricks. How? Keep reading.

I will first talk about Sex Differentiation. To all the boys reading this, did you know you had a uterus once? Well, you kind of did. You had something called a Mullerian Duct, which could have turned into a uterus and a vagina if you didn't have a Y chromosome. So what happened to it? It got destroyed when you were in the womb because the womb saw you had a Y chromosome and you had to be a guy. I'm kind of getting ahead of myself here. Let me step back a bit. First of all, what is Sex Differentiation? It's when your body when you were in the womb finally decides if you're going to male, female, or Luis. It happens during 6-8 weeks after your mom got pregnant. Before that, everyone (male and female) had something called the Wolffian Duct, the Mullarian Duct, and the Gonads (which turns into balls if you're male and ovaries if you're female). They were like your prototype genitalia. The Wolffian Duct will develop into the vas deferens (the thing that guys have) for guys and Mullarian Duct will develop into a uterus for girls. Of course you can't have both (unless you're Luis) so how does your body decide what to keep and what to get rid of? The Y chromosome decides. The Y chromosome has a gene called the SRY Gene which tells your body to be male. The SRY gene also tells your body to continue developing the Wolffian Duct and to get rid of the Mullarian Duct. However, without the Y chromosome or the SRY gene, your body does the exact opposite. When you think about it, if there is no response from the Y chromosome, you will automatically be female. So, just get rid of Luis' Y chromosome and it's gg? Nope. It's not that easy. You can't just rip out a chromosome like that. There is another way that could turn Luis into a girl (biologically) while keeping his Y chromosome. How? Keep reading.

The second thing I will talk about is X Inactivation. To all the ladies reading this (including you Luis), did you know we're only using one of our two X chromosomes at a time? It's true. But why is that? You see, the X chromosome has a lot of important genes that aren't just sex related but the X chromosome has genes for your muscles, eyes, etc. The thing is, the body (both male and female) only needs 1 X chromosome active at a time. If 2 were active, it can cause the 2 X chromosomes to conflict with one another. One X chromosome wants green eyes, other wants blue eyes. How does the body fix this? X Inactivation. As the name implies, one of the X chromosomes is deactivated. When you think about it, females only have 1 functioning X chromosome at a time. You see, the human body can function with only 1 X chromosome. What about guys? Well, guys only have 1 X chromosome so X Inactivation wouldn't work. But what about the Y chromosome? That's just to keep guys as guys. So in effect, females have 1 functioning X chromosome and 1 deactivated X chromosome while males have 1 functioning X chromosome and 1 functioning Y chromosome.

Remember how I said if there is no Y chromosome during Sex Differentiation, you will turn into a female? Well, I have an idea. What if you could deactivated the Y chromosome BEFORE Sex Differentiation? Wouldn't that effectively make you a female with 1 functioning X chromosome and 1 deactivated Y chromosome? Yep. Of course I can't experiment this due to "ethical" and "moral" issues but yes. It could be possible to turn any guy into a female if you can somehow go back in time and shut off their Y chromosome before the 6th week.