20Liam's Inconsistent Aging
Given the fact that the majority of the first three or four years of Shameless are supposed to take place within a fairly tight timeline (roughly 2 - 4 years), it's fair that the filmmakers have kept Liam so young. But after time started to move more quickly, it's hard to
understand why Liam just didn't age.
In fact, he didn't really start to age until season 7, when the filmmakers stopped using young sets of twins and hired a slightly older actor, Cristian Isaiah. This was a welcome change since Isaiah is such an engaging actor, but it did bring up more issues surrounding the true age of the character. Liam's strange aging process tended to stand out against his older siblings, who aged far more traditionally.