Oh there must have been an Adam and Eve.
If there was only an Adam we would not have all these magnificent Eves to get us into trouble.
If there had been only an Eve what a pain life would be for you Eves, how could Eves go shopping without an Adam to carry their bags.
You see Adams are not bright enough to invent Eves and if Eves had invented Adams well... we Adams would all be very different.
So they had to be a common arrival of Adam and Eve.
I would not have it any other way.