Funny you should ask! I actually haven't seen Dead Ringers, but it's on my to-watch list largely because of the Underwood twins. While Bertrand has no medical aspirations, from everything I've heard about the movie there are definitely some clear resemblances and I look forward to watching it.

As for the inspiration behind Bertrand and Alec, it's kind of a long story. The short of it is that I had Alec first, but wrote him as an only child for many years before toying with the concept of an older brother. It was through many long nights of character discussion with my dear friend Hajo that I discovered how well he'd be suited by having an older twin brother, and we developed Bertrand from there!