[Sir Francis Dashwood]

I have purposely tried to leave sex out of this discussion...

Why?

Mammals can only "evolve" with heterosexual relationships.

Genesis confirms this idea...

Regardless of what we might think about polyandry or polygyny, there is no actual prohibition of it in the Bible.

But, there was a city called Sodom completely obliterated.

[Cronos]

Sorry, but polyandry is specifically prohibited -- Leviticus 20:10: “‘If a man commits adultery with another man’s wife—with the wife of his neighbor—both the adulterer and the adulteress are to be put to death.

yes, technically she would also be his wife, but she's also another man's wife.