i 'd say your wrong.
since mammels developed evolutionary from Birds/reptiles/amphibians ur biological standpoint isnt that bio - logical.
they all have a cloaca!
http://en.wikipedia.org/wiki/Cloaca
so you see from the evolutionary point of view , which repeats itself in the embryonical devolpment of every biological being, the anal canal and the sexual organ were one for a long time.
you can think about that the next time you eat an egg.
your biological standpoint is purpose oriented and leaves out how somthing develops.
that's -besides being unbiological -pretty undaoistic from my point of view. since it is a daoist tradition to learn from animals - especially today with the knowledge about evolution.