1. Men are now superfluous.
Historically men have been useful for
but technology can do the fertilising and heavy lifting and technology permits women to be soldiers. (If men were entirely phased out people would abandon soldiering.) Women can as easily support mothers and their children. Men no longer serve any purpose.
2. The essential contribution of men has always been tiny.
A child begins as an egg in a female foetus within its grandmother's womb. After its mother's birth, it stays dormant in the mother for 13 years or more then migrates into her fallopian tube. There, it encounters a few cells from the father which supply DNA which trigger it to develop. The father contributes only the DNA command, no nutrient support.
The mother's body supplies nutrition and immune protection for the next nine months then her birth canal painfully smears bacteria on the child to protect its skin and digestive system. The breast-feeding mother continues to supply nutrition and immune protection. Her kisses pick up its infections, and she makes antibodies and gives them to the child in her milk. The father does nothing. If he kisses the baby and infects it, the mother's milk will have to counter that. Essentially, the male mammal is a parasite.
Artificial insemination is simple and easy. There is presently enough frozen sperm in store to fertilise many generations. Technology will soon allow DNA from anyone to fertilise eggs, rendering male sperm unnecessary.
3. Advantages of phasing out men: remove the cause of the world's strife.
A. Save needless suffering and expense
by drastically reducing:
and by eliminating:
B. Identity resolution. Boy children look to men as role models. But nowadays men don't know what role they should be filling so boys are confused. No one knows how to be male; no one knows the point of being male. Women have no identity problem; the point of being a woman is quite clear.
C. Better health: boys and men are sicklier and less physically tough than women and girls.
D. Equal rights by allowing everyone to bear and suckle children instead of only half of them.
4. Advantage of retaining men: entertainment.
Adultery is quite common which mainly shows some women do not like the man society has bound them to but it also indicates that some women find some men entertaining. Is the entertainment value worth the cost of keeping men? It would be immoral to inflict maleness on half the human race in order to entertain the other half. The entertainment difference is anyway probably a result of female socialisation and, given the opportunity, women would be just as entertaining.