Nuetering a dog with pregnant dog in the house

Question
Less than a year ago we purchased a pair of cocker spaniels that were on their way to the pound.  My husband wanted a litter before we had them "fixed".  He got his wish and now the female is pregnant.  Now I want the male dog nuetered ASAP.  Our only worry is that after he is nuetered he may become aggressive toward the pups.  Is there any validity to our concerns?  We have about 4 more weeks to make the decision.

Answer
Hi Jerri!  There is no reason for concern. Neutering him would actually be the best thing, as neutering a dog tends to make them less aggressive. Neutering a male decreases the chance of testicular/penile cancer by 99%. Either way, it is a good idea to keep some space between the "father" and the litter, as males do not have the maternal instinct that females do.
After the litter, spaying the female would also be the best idea. Spaying a female dog reduces the chances of her developing uteran/vaginal/cervical/mammary cancers by 98% and also eliminates the chance of her developing a deadly uteran infection called Pyometra.  
I hope this helps and best of luck on those pups!  Keep me posted!
Hilary