Update: I had a wrong assumption.
After triple checking, I now see that how ordinary monozygotic twins arise is 1 sperm and 1 ovum and then later the zygote splits up.
- (1.1. and that that phil and lil from rugrats are opposite sex and identical twins is actually an extremely underrated genetic miracle, possibly giving more credibility to the rugrats theory/hypothesis. There's also semi-identical twins in a song of ice and fire - though i guess not game of thrones -, Ben 10, legend of korra, KND, baka to test, and i think samurai jack, etc)
Honest to God, what i weirdly remembered was that ordinary 'monozygotic' twins arise from 2 sperm 1 ovum and then this 'zygote' or whatever of 2 sperm and 1 ovum splits up into 2 zygotes i.e. the splitting up of the 'zygote' is a natural consequence from that 2 sperm have fertilised 1 ovum. From what I weirdly remembered, it would be natural to ask what if the 2 sperm were from different males.
- (2.1. Additionally, the Phil and Lil thingy is not really a genetic miracle since all you need is a 22X sperm and a 22Y sperm to fertilise 1 ovum. Damn television. i really thought opposite sex identical twins were not that rare.)
However, apparently it is possible for 2 more sperm to fertilise 1 ovum, in a case called semi-identical twins or something, but there are apparently only 2 reported cases.
New question: Okay in the unlikely event that what would be semi-identical twins would arise from sperm from different males, well, then what?
From wikipedia:
Homopaternal superfecundation refers to the fertilization of two separate ova from the same father, leading to fraternal twins;6 while heteropaternal superfecundation is referred to as a form of atypical twinning where, genetically, the twins are half siblings.
There doesn't seem to be a distinction between heteropaternal superfecundation occurring with two ova and with one ovum. How will monozygotic heteropaternal superfecundation twins look like as opposed to dizygotic heteropaternal superfecundation twins and to identical twins?
Are/Were there real life cases of monozygotic heteropaternal superfecundation?
The heteropaternal superfecundation selected cases given on wikipedia seem to be for dizygotic. I tried looking up on google, but I've found so far only dizygotic.