Scully and Mulder in “Roland”

Scully

Arthur and Roland Grable, born at Puget Presbyterian to Mr. and Mrs. Louis Grable on July 15, 1952. Arthur was four minutes older than Roland.

Mulder

Identical twins.

Scully

Which means that they're the result of a single egg fertilized by a single sperm.

Mulder

I've read studies which suggest that in some cases the identical twin arises very early in the embryonic stage when a mutation in one cell is rejected by the other cells as foreign.

Scully

So that maybe Roland's condition is the result of a damaged chromosome rejected by one of Arthur's cells?

Mulder

In a way, that would explain Arthur's genius and Roland's strange mathematical gift.