neutering?

Question
Hi! I have a few questions for you if you don't mind.
Would it be better to have a spayed female and an intact male together? Or a neutered male and a intact female together?
Does a spay cost more than a neuter? Which one is less painful and stressful? And would it be okay for a female rat over a year to be spayed? Would it prevent tumors eventually? And how do a male's testicles look when he is sexually mature? I think the all-female Petsmart nearby sold me a male rat and now I need to figure out how to talk my parents into letting me keep him. He's in with the older female right now, and they're getting along really well. I don't think he can make babies yet because it's not that obvious that he's a guy other than the bump near his rear...
I appreciate any help you can give me, and I look forward to hearing from you.
Thank you, Ally

Answer
If the rat is 5 weeks old (the male) is is absolutely able to get a female pregnant, despite how wee his testicles may appear.  You need to remove him from the girls cage now, and lets hope its not too late and nobody is pregnant!

Spaying is more invasive than a neuter but spaying prevents mammary tumors from developing. However this should be done young, around 3 to 5 months of age in order to really prevent mammary tumors later in life.   Spaying also prevents uterine related problems like tumors and infection, so I would have the females spayed but the vet MUST be very skilled with surgery and rats.   Do you have a vet for your rats that is an exotic vet?