Nobody ages

This one is the biggest of the lot so it should open the list "“ ever since the new trilogy began, none of the X-Men members, nor any of the human supporting characters, seems to age. This can be explained for characters such as Mystique, who is a shapeshifter, meaning that she can choose to look younger; or Wolverine, who possesses an off the charts regeneration ability (but still looks older than he did in 2000). But what about all the other mutants? Do they also possess this kind of ability, as well?

It’s even weirder with the human characters "“ for example, Moira MacTaggert doesn't age a bit in two decades, a detail noted by Professor X as well.

And the blame for this rests on Bryan Singer, who’s the one who decided to set each of the movies – after First Class - in different decades. Why? Well, I have no idea why he went this route. But something needs to change, and it needs to change before the next X-Men movie arrives.

Don't set it in the "˜90's.

But hey! The characters don't age in the comics, either. So maybe this is the most plausible explanation.