I'm sure there were rules for playing monsters as a player class and/or taking levels in their Monster class (i.e. Becoming more representive of their race).

Now, maybe looking at a book like the Book of Erotic Fantasy (I belive that was that book's name...but, what it did was add like rules for love and pregnancy) might give some insight into how conception might occur.

One thought would be the Priest appealing to his/her deity... Also, there is no explicit rule stating that said races cannot conceive (only the rarity of said conceptions not generating an explicit entry in a rule book)

I'm sure there were rules for playing monsters as a player class and/or taking levels in their Monster class (i.e. Becoming more representive of their race).

Now, maybe looking at a book like the Book of Erotic Fantasy (I belive that was that book's name...but, what it did was add`like rules for love and pregnancy) might give some insight into how conception might occur.

Ok, The Book of Erotic Fantasy p49-50

CrossBreeding: ...sex between different species happens with unusual frequency. Creatures of the same type (humanoid, monsterous humanoid, etc.) are able to produce children, though this progeny is a half-breed, with traits from both parents...

One thought would be the Priest appealing to his/her deity... Also, there is no explicit rule stating that said races cannot conceive (only the rarity of said conceptions not generating an explicit entry in a rule book)