Why MEN?

Why do we have two sexes. Or more specific: Why do we have men? 

Why waste all that effort and energy in producing and caring for offspring that doesn't carry offspring themselves? Kinda pointless, right?

The maintenance of sexual reproduction in a highly competitive world has long been one of the major mysteries of biology given that asexual reproduction can reproduce much more quickly as 50% of offspring in sexual reproduction are males, unable to produce offspring themselves.

"Almost all multicellular species on earth reproduce using sex, but its existence isn't easy to explain because sex carries big burdens, the most obvious of which is that only half of your offspring—daughters—will actually produce offspring. Why should any species waste all that effort on sons?” lead researcher Professor Matt Gage, from University of East Anglia's School of Biological Sciences, said in a statement. 

Researchers from the University of East Anglia (UAE) believe they may have found an answer, suggesting that the evolutionary force known as ‘sexual selection’ plays a key role in improving population health and protecting us against extinction.

"To be good at out-competing rivals and attracting partners in the struggle to reproduce, an individual has to be good at most things, so sexual selection provides an important and effective filter to maintain and improve population genetic health,” said Gage. 

So - 2 sexes is a major asset, when it comes to a species survival in a competitive enviroment. But would it be so universal that we would expect to find it on other worlds as well?