I don't think there was - in fact, it was explicitly stated that making Adiposes out of non-fatty tissue made the child-Adiposes sick. Which was rather an odd thing to include, now I think about it - if they had just not mentioned that bit, then the Doctor's actions would have made more sense as we would then have assumed that the reproduction would continue until the host died. Peculiar.

I caught a bit of the Confidential afterwards and Russell whatsisname was saying that he thought the Adiposes were sinister, so perhaps they were relying on the 'ick' factor to explain why this was considered so awful. I thought they were cute, personally.