Well :
Sexual :
Benefits - Your child will look more like you, and will have more of your genes and DNA
Harms - It takes a long time, and something may go wrong with the birth o the mother or child. (Your idea : STD - sexually transmitted diseases.)
Asexual :
Benefits - It is faster, and won't have as many problems as sexual.
Harms - Your child won't look as much like you, and won't carry as many genes and DNA as sexual does.
Hoped I helped!
(Btw : Humans only reproduce sexually)