Oh... and just my personal opinion here but there are certain non-mutable traits an animal posesses which should be covered by a longer guarantee period. "Healthy" can change if the buyer isn't knowledgeable enough or accidently exposes the animal to dangers... Gender doesn't, genotype doesn't... So if a dealer offers 48 hours-two weeks or whatever for health, I believe that there should be a longer period of time during which the customer should verify any important selling points like gender... I do not think it should be guaranteed forever though, anyone who really needs to know the gender of an animal should be able to determine it themselves (when possible) but I understand that not everyone can pop or probe a snake and that some lizards have males which aren't as obviously developed and mistakes can happen... Giving a buyer a month or so to hunt down someone who does know how to verify the gender is only good business but it all becomes sticky if they find out the animal they bought isn't the animal they reccieved a few years later when they go to breed it (although nobody seems to complain when there's a price difference in their favor).
"Genes, Like Leibnitz's monads, have no windows; the higher properties of life are emergent... And once assembled, organisms have no windows." - Edward Wilson, Sociobiology