when can a kitten get pregnant?

Question
have two kittens. a male who was born july 16th and a female born sept 1st! I noticed last night the Oliver ( the boy) was biting Maddies( my female) neck and trying to mount her! Maddie is only 4.5 months old and hasn't gone through her first heat yet...can she still be pregnant?! Of course the vet isn't open today and I have seperated them but Oliver is scratching the doors like crazy and crying. can Maddie be pregnant?

Answer
Hi Charlene,

I hate to let you know this but cats can go into heat as young as 4 months. It is rare but it does happen. It sounds like Maddie might be in heat. You have a few choices as to what to do. You can keep them separate like you are now. You can get Oliver fixed. You can get Maddie fixed. Or you can get both fixed. I would suggest getting both fixed. It makes for a much more peaceful home. Good luck.

Ciao, Karen