I've read the suggestion that intelligence doesn't conform perfectly to the bell curve. There is a bit of a bump out at both tails. At the low end - poverty as noted, but also genetic conditions that affect IQ, brain injuries of various types, etc. Some have suggested that some modern changes have made it so high IQ people are more likely to mate with high IQ folks (more mobile society, women having more choice, geeky IT guys having skills that are more valued). Same factors that some suggest are related to the increase in quirky/autistic kids.
Yep, I tend to agree with that. DH and I are a pretty good example (met in grad school in a field that typically women weren't in previously and now have a quirky kid). I'm not sure, though, if it will actually increase the number of gifted individuals or if it will just make it more likely to predict when a child could be gifted. Previously, if you had couples marrying more for geographical or financial reasons or even quasi-arranged marriages than you could more easily have a gifted+average couple marrying and reproducing so the kids would have a *roughly* 50/50 chance of being gifted. But depending on the genetic history of the family it might not even be 50/50. Say if the gifted adult came from a gifted+average coupling than maybe it would be only a 25% chance? Also even if you did have two gifted parents there might be more non-gifted genes floating around from their ancestors.
In theory, now it's more likely that you have two gifted adults reproducing (due to jobs, women in the workforce, mutual interests etc) and over time it'll probably be easier to predict that if two gifted adults have a child than their child will also be gifted. Obviously there are a million caveats here but I would guess this could be a trend we see in the future. Just from the one data point that is my life I've seen most of my friends marry people that are roughly at about the same intelligence level as themselves. They might present radically differently (audio sequential vs. visual spatial learner, gifted in language arts vs. math etc) but they are normally in equal pairings. I only know one example of a family that is at really different levels and I suspect the one at a "lower" IQ level actually has a learning disability so then it's hard to say for sure.
Granted there's also been an increase in sperm/egg donors and things like high IQ sperm donors are popular so I have no clue how that plays a role here.
ETA: There is always the "idiocracy" argument that high IQ families tend to have less kids because those in demanding careers do tend to have smaller families and sometimes these gifted kids can be quite demanding. But that also ignores the fact that many times either a man or women will give up a demanding career to raise the kids and that there are other gifted adults who were never identified or chose not to have a career for a myriad of reasons.