FAIRY REPRODUCTIVE ANATOMY
Okay guys time to discuss fairy reproductive anatomy! We'll only be talking about cishet fairies here, so keep that in mind.
When it comes to fairies, their sex organs are "switched" so to speak, in comparison to humans. Males have a vulva and uterus and females have penis and testicles. However, the female fairies produce ovum and the males produce sperm.
Fairies of both sexes are fertile once a month, wherein the female produces a single ovum and the male produces numerous sperm. Unlike human gametes, the ovum is covered in cilia (hairlike structures that allow for motility) and the sperm lack flagella (tail). Here's a diagram on the morphology of fairy gametes in comparison to human gametes.
Much like humans, fairies show no signs during their fertile period and rely on medical devices (similar to ovulation strips for humans) in order to know. Male fairies can get a good estimate by tracking their menstruation cycles, of which lasts for a month.
When female fairies ejaculate, they release a single ovum which then travels to the fallopian tubes. It reaches one of the sperm and absorbs it into itself. This results in fertilization.
Pregnancy lasts for three months. During this time, the pregnant fairy will experience mood swings and constant nausea and vomiting. The reason for this is because the fetus generates a lot of magic. This results in something similar to magical backup. The vomiting is the body's way of getting rid of the excess magic. Although unpleasant, it's a normal and healthy part of fairy pregnancy. The worse a fairy's nausea and vomiting is, the more potential for magic, ie. inherent ability to perform spells and such. This is why Cosmo had such bad nausea and vomiting when pregnant with Peri: because Peri had a high magic potential.
Although it's the male fairy that gets pregnant and gives birth, it's the female fairy that breastfeeds the baby. The magic produced by the fetus not only affects the father, but the mother as well, though to a lesser degree. Both will experience bodily changes as pregnancy is something that is experienced by both parents. The female will develop fuller breasts and will begin to lactate shortly after the male has given birth.
A female fairy will only experience symptoms as long as she is within proximity to her partner on a regular basis. If the fairies aren't together frequently, the female will experience no symptoms and won't lactate. For this reason, it's expected that a fairy couple will stay close to each other during the duration of the pregnancy. If the female fairy is away from her partner for too long, she might not produce enough milk to feed the baby when it comes.
Why do pregnant fairies have difficulty giving birth? Simple; after hundreds of thousands of years of magic advanced enough to poof their babies out of them (I'll discuss this in a different post), fairies have forgotten the instinct to push during labor. Why would they need it when they can just poof the baby fairy out of them?
I'll make a post about fairy gender and societal expectations and go more in depth on their reproduction, so stay tuned!