What timeframe is this? Like, if Victor VonDoom marries Sue (not Reed in this continuity, but the woman who would have been) and has a child, would that child be old enough to be a PC, or still too young?
It'd be fun to do a gadgeteer sort, but I don't fancy going full-on Doom.
I have other notions too though...several, in fact...
Age in comics is always so awkward. You can make up your own independent backstories, and I'll work around them. If you want your character to be Doom Jr., that works great for me. Of course, if the idea clashes with another PC, then we'll figure out a way to work around it.
Like if Doom Jr. is Sue's son, maybe Insight's Franklin character could be his half-brother (drama!) or simply unrelated figures whose families have had a few nasty run-ins.
Insight: Franklin is a great idea. I think he's a really interesting character, so I'm excited to see what your final product looks like.