I am not sure who you have been talking to, but this does not seem entirely unusual to us. Granted, it is more common with dogs, or at least female cats, but every animal has an instinct towards being protective of younger cats. The way I think you should see the situation is to be grateful that your male cat has accepted the kitten so readily and is not acting aggressive in any way. The only way I can envisage a problem is if he becomes over protective of her, or demonstrates obsessive behavior. Make sure that he does not mind spending time away from the kitten and that he will be happy for you to play with the kitten on front of him without any jealousy. Problems may only arise once the kitten is older and wants to be more independent. Your male be less happy if the new kitten wants to be the dominant cat in the household!