The New York Times has an opinion piece about the possible—inevitable?—disappearance of male humans.
It also publishes the obituary of Adrienne Asch, a philosopher and bioethicist who supported abortion as a right but opposed pre-natal testing and abortion "to select children free of disabilities." She saw no conflict in the positions.
Perhaps as a member of the gender on the evolutionary road to extinction, I should not be allowed to comment. Additionally, I've not read enough of Asch to understand the full measure of her argument.
As to the first supposition, if you've ever lived on a farm—at least one that uses artificial insemination to improve a cattle herd—you'll understand males aren't really necessary, at least in large numbers. In fact, the world could do without human males now, other than a few thousand to assure genetic diversity, and inevitably, science will eventually progress to the point that parthonegenisis will be possible.
It's an interesting possibility, that world. No war? A more humane, empathetic society? There is more than one study that posits that an imbalance of males (more males than females) leads to more aggression (war). Are you listening China? So, no males, more empathy, a kinder, gentler world society, until females evolve ... or rather, devolve.
As to the second thesis, Asch, in her good work, may have been tilting at existential windmills. There are statistics floating around that suggest 90% of babies with Down Syndrome are being aborted. I know there are other genetic screening processes, especially related to inherited mortal diseases.
There is also "selective reduction" when multiple babies occur after treatments for infertility. For someone who has known childless couples, and their pain, it is a source of joy that medical processes have grown so sophisticated that a baby may be brought into the world to fill an empty heart, but there's something ugly in the utilitarianism result where two will be fine but let's throw this one away.
I suspect one day there will be no male humans. I suspect before then there will be no babies born with disabilities, babies born with certain genetic traits (blue eyes, anyone?), and babies born because the parents wanted a little girl rather than a little boy.