Board Thread:General Discussion/@comment-25301131-20150310010922/@comment-24870482-20150815220913

Thank you! Different fingerprints are a but if a stretch to be compared with a different number of fingers. Though they look incredibly similar, extra fingers are a but of a stretch.

Additionally, though the number of fingers (I guess) are a phenotype, they are expressed from a genotype, which Lee would have to have as well. Although there are environmental influences on the phenotype, I am unsure what could have possibly happened in the womb for him to have an extra finger, seeing as how unlikely it is for him to have been injected with like, toxic waste or something.

Admittedly, this may be the point — Ford knows it's weird and that's why he's drawn to GF. Maybe all will be revealed later. I don't know, he might be an alien or whatever.

Frankly, that's the best explanation.

Also, there is no way Mabel and Dipper are identical (duh)