Eugenics/Designer-babies... is the concept really that bad?

[FatAndFaithless]

Exercise a little critical thinking. If people aren't getting sick, they're not dying, living longer, consuming more resources, and generally more likely to do lots and lots of fucking. Overpopulation would become the one 'disease' that can't be overcome. Building in a safety net against that would be the only logical thing to do rather than asking people to use their own discretion in birth control and contraception. If all the important shit is done in a lab anyway, fertility doesn't seem to need to happen anywhere else. Besides which, as I mentioned earlier, parents can be screened and evaluated for fitness in child-rearing so that unfit and abusive parents or those in an unstable and financially rocky situation don't end up with kids they can't properly care for. There's literally no downside to this.

Where on earth did you get the idea that health and economic prosperity correlates with having too many children?

No kidding.  The average number of kids per family in the US has gone down as life expectancy and quality of life has gone up.  You don't NEED to have 8 kids anymore because 3 die before the age of 30.