The vet says she's a male

hi everybody,

I bought a kittie about two months ago ... The seller and someone who helped me buy the kittie said that she's a female and her name is "Barbie" .... Mom didn't want cats at home, so i had to give Barbie to a classmate of mine to give her to a family for a while until mom calm down .. After 18 days, he returned the kittie to me and said that the family doesn't want her coz she doesn't use the litterbox all the time and sometimes does her business on the ground .... yesterday, i took her to the vet and asked him to check if she's a male or female coz i never checked that since i bought her, he said "it's a male" .. i got shocked and now i don't know whether this is my kittie from the very beginning or my classmate subsituted it for another one ... the one thing that says it's my kittie is that my kittie though having all her fur white, she had a black hair on her head and this one i have now has the one black hair on the head too ... As for whether i saw her sexual organs b4 giving her to my classmate, i always saw something on her belly between her legs like a navel ... i wonder if you can help me by guiding me and i will be grateful if u have pics showing the differences between males and females .. my kittie is now 5 months old and i bought her when she was 3 months old and she stayed with the family for 18 days and i got her back since 24 days ... thank you and hope u can help me ..

Take a picture of her "bottom" area and I can tell you the gender. Lay him/her on their back and get a pic directly between the legs, if possible.

Otherwise... you can go off these pics
http://www.thepetcenter.com/exa/kitx.html

If your kitten is 5 months old now, it would be more obvious if it was a male as you would see small testicles. IMO I like males better - they are more outgoing and accepting of new things.

Just get him neutered now before he develops bad habits like spraying. That could be the reason he was not using the litter pan - he was starting to mature and spray.