TL; DR: Rest assured, biology rules means no mammals can make clones of themselves. A particular lizard can and bananas show us why that would be a problem.
Though much of omegaverse has to ignore our biology rules, I can assure you that you cannot get pregnant with a clone of yourself. Nearly all the eggs in an ovary are made while still in the womb. When girls start puberty, that's the first time they "come online." Our immune system is designed to delete anything that doesn't match our DNA except in the uterus. If, for whatever reason, an egg does have our full DNA, it doesn't undergo the reaction with sperm because it is already occupied and therefore, it cannot adhere to the uterine lining. And IF it manages to do so despite those odds, because of where it is, the immune system will classify it like cancer so it will take it out. (Your immune system does that constantly, by the way; the cancer we treat are the cases where the system failed or could not keep up with the growth.)
Males make sperm for life and can do so multiple times a day (quality declines with age.) There are many failsafes that immediately take out defective sperm before it even has a chance to leave the body. However, some infertility problems do occur when the sperm, say, doesn't develop the correct tail so it can't propel into the uterine tubes.
A lot of things have to go correctly for conception to even occur that looking at the full view of it seems like playing the lottery. Wait, it's easier to be struck by lightning; let's go with that. Regular pregnancies are lightning and the chance of self-fertilizing is the lottery (one in which the winners don't even know they won because their body said do not pass go, do not collect $200.)
There is a breed of desert lizard which are all female clones of each other. The problem with this, which is why we don't do it, is because that leaves the entire species vulnerable to the exact same diseases.
A modern example is the banana you get in nearly all grocery stores. It's the same kind so if the trees come in contact with a fungus, that could wipe out the whole production. If it isn't caught soon enough, it will also spread through other plantations and wipe the fruit off the map. If you have ever had Runts candy, the banana flavor is based off of a banana that had been popular back in the 1920s that ran into this fate. But because a hundred years have passed since then, it seems artificial because we only have one commercial banana to go off of. If we have any other types of bananas, they are only consumed within the growing community (the best watermelons are consumed this way as well because they will explode during transport.)
I just thought about this but in omegaverse, since males can get pregnant does that mean that they can use they’re own cum and have their own child like It just came to mind and I’m like they can get pregnant but can they do it themselves or whattty