Being natural hermaphrodites seems to work well for earthworms, but most other natural animal species NORMALLY have male and female in separate bodies.  Is having male and female in separate bodies a practical reproductive plan for humans, mammals, birds and etc?  In Man's various cultures, this separate male and female setup seems to have been the cause of a lot of social inequalities since man first picked up a stone and cast it.  One such sex inequality invented by Man has been "ladies first"