I think as we see this changing and blending of roles in male and female, will also slow down the population explosion as dogmatic religions are slowly put in its place. I think in time our species will evolve to blend the two sexes, and bring about a more ecologically friendly species, if not we will become extinct.
Frankiespeak, If we accept our wholeness (our chromosomes make us male/female only to preserve the species see "the Selfish Gene" by Dawkins, I think by Dawkins ? anyway) Then becoming asexual would be counter culturally evolutionary. And considering that culture and society and communication are the very things which caused humans to evolve speech and share ideas and inventions , well asexuality seems more anti-social. We were ecologically friendly or rather the environment was friendly to our species. Only when we all realize our importance in being the Jeffe group (for good or not) and restrain ourselves out of our great love of life; and then apply our great big brains to healing our planet (like you said) only then will we breathe in the good and satisfying changes. I don't promote going back to anything or time , but change is good even if at first unsettling.
The idea previously mentioned of becoming bright (Brights?) illuminators of our fellows will make us much happier with who we are and less apt to continue to destroy the environment (thus destroy ourselves).
The USA isn't overpopulated. However people have the notion that they WANT children. Not for the childrens sake but out of selfishness. If you really want to help an individual (ie., your offspring) you'd raise each child with all of your energy and resources. Unfortunately, our society has so convoluted sex that our kids have no idea how to NOT get pregnant with children whom they (unprepared parents) have nothing to offer. Our kids are propagandized about sex through the media (be hot and buy this ...) and then many schools allow the silver bracelet of chastity till marriage crap. Shoot we are sexual beings for sure , why not teach our children respect for themselves. And if we are able to teach that we'll be on the road to positive change.
We won't ever be perfect. We'll always have the cornucopia of life experience. I think that's good and it makes the statement "live and learn" take on a positive note.