Imuran and Fertility

Just a quick question regarding being on Imuran/azathioprine and male fertility. My wife is currently 7 months pregnant with our first daughter, and we couldn't be more excited. During the time she got pregnant I had been off of Imuran for about 4 months so we had no issue the first time. Shortly after our daughter comes we are thinking of having another, but, I don't think I want to try coming off of Imuran this time while trying to conceive. It is the only medication I am currently on and I believe it is doing its job. From the research I have done I have read mixed opinions on if it is indeed safe to be on Imuran or not. I was trying to find out first of all about fertility issues, and also of course birth defects. Anyone have any information on this subject or have recently given birth while either sex has been on Imuran?

Thanks for the link. I will give it a read.