Hello from another childhood ALL survivor! (right now my major role is as caregiver to my parents - Dad has cholangiocarcinoma and my Mom has bone cancer) but I am a survivor too!!! I think that fact also encourages my parents!
Anyway, I was 13 when I was diagnosed and went through about 3 years of chemo; including 10 rounds of cranial radiation. When I was 23, I had a check-up and my boyfriend came with me. We learned that there was a strong possiblity that I couldn't have children, and if I could that my "window of time" was a lot shorter than normal. The doctor said this was because of certain drugs I had been on during chemo. I honestly cannot remember which of the drugs was the biggest "culprit" - although I think it might have been Cytoxin... I just cannot remember for sure.
We've been married now 10 years (he asked me to marry him the week after that check-up and we got married three months later!) and we are still childless. Although I do know of other survivors that have gone on to be parents. It really seems to depend on what type of chemo you took and what age you were when you were on meds.
Best of luck!
N