Hi Dan,
over the years I have seen incompatible pairs of many reptiles. They look the goods but when together just dont do well. I have an olive python that I loaned to a really good breeder and he has found to date that his female has no interest in the male and vice-versa. Can this be changed? I think in some instances it can, especially with pythons, but it does involve some manipulation and the smell of another boy. For this I tend to use a recently shed skin from another boy that the original boy has not seen or met before. Some male pythons are not interested because in the past they have been brow beaten (or really beaten) by a rival male and 'remember' the experience. I liken it to the single guys who frequent bars looking for a fight with another male because they are not good at talking to the fairer sex, so they know they don't stand a chance at enticing a lady there but might be able to get some standing among peers (homosexuality is also innate in the animal kingdom, and the fight may be some courting ritual?). This fear or apprehension with the opposite sex appears to happen to some male pythons, olives especially, so it is a matter of retraining for them to believe they can get the girl. Hence the skin from a male they have never met that gets put into the cage with the pair when there has been no activity from either partner after a week or so. I keep skins of other snakes in the Freezer in separate zip lock bags and thaw them out and just lightly mist with water before putting them in the cage as needed. The skin will only be in the cage for a day or so and goes in late in the afternoon as the night time temperature is dropping to hopefully stimulate both a male and female reaction. Separation is also so important in many pythons. You have all heard the adage 'distance makes the heart grow fonder,' so to separate during the feeding months and early cool season and introducing during the breeding season is also very important. Reptiles dont like each other and most will at best tollerate one another, so to keep them together defies their natural instincts - but we do for space constraints. In the wild they live very separate lives and come together in the mating season only - gives some good indicators I think. Hope this helps.
Cheers
Gavin