We are not asexual but it is definitely possible for two females to reproduce by using genetic engineering and the offspring will always be female (no Y chromosomes). Basically, the genes from one egg would be taken and either implanted into a sperm or directly used to fertilize the other egg. It has been accomplished in test animals so THEORETICALLY we could have an all-female world.
OTOH, we aren't too far from artificial wombs and surrogate mothers are fairly popular. With genetic engineering, two men can have offspring. However, half of those offspring would be female since all men carry one X chromosome. With screening, selective abortion, etc it is THEORETICALLY also possible to have a world of only men.
The world will definitely be a very different place within a few decades. I believe it will be a better place and the above will never happen, despite what doom & gloomers say.
We’re talking natural selection here, not genetic engineering, or invitro fertilization, or even nongenetic preferential selection. Anomolies tend to either adapt or disappear in a small timeframe. Until I see the first human asexually reproduce, it isn’t going to happen with the DNA we have.