Originally this was meant to answer the booger-eating thread in the Temp Forum, but there is too much good science here to not share it with a wider audience.
Eating boogers can help boost your immune system. Seriously! The boogers contain all sorts of bacteria and viruses, which are taken up in the digestive tract. The outer layer proteins, which are essential for recognition by the immune system are then, by some ways which are not well-understood, send to “memory cells” of the immune system, so the next time your body comes into contact with them it can react much faster.
A lot of children eat their own boogers when they are young, so they might instinctively know what’s best for them.
On a different note, it was shown in another study, that women who practice condomfree sex with a longterm (only longterm!) partner before they conceive, experience less complications in pregnancy (those based on different bloodtype for example) than those who used condoms. The surprising finding was, that even condomfree ORAL sex had this effect. Because some semen invariably ends up in the digestive system, it might be speculated that the female body becomes “familiar” with the features of the partner over time.
What exactly happens is not clear and the study was statistics-based (the sample was a group of female college students), but the basic mechanism between booger-eating boosting your immune system and condomless oral sex preventing complications in pregnancy might be related.
So, good news for everyone! Mothers can happily let their children eat boogers and future dads can tell their partner “I think it’s better for you we don’t use rubbers from now on.”