So kids are forgoing realworld sex. When did that become a bad thing? My whole school life I was 'encouraged' to avoid sex, alcohol and every other vice at all costs. Going to a party on a friday night was a bad thing. Sex, whether through disease or pregnancy, would destroy your life. This is still the mantra, although nobody then told me that sex would send me to hell. That part is new. So why are we not surprised…
This is exactly why I'm not so worried about overpopulation or even immortality. In fact, it's going to get a lot "worse" when you know you're immortal. Why would you have kids by 30 or 40 then? Heck, why have kids by your 1,000th anniversary?
There are most likely some people who would want to have kids under those circumstances. To the extent that the traits that lead them to act that way under those circumstances are heritable, either genetically or through parents-raising-kids (some religions are obvious candidates here), these traits would be selected for in subsequent generations. If a supermajority of people lack these traits, the problem may be put off for some generations, but eventually it will make itself felt. That said, I think there are a few possible solutions, and I certainly am in favor of developing immortality.