I've still only heard of one guy who hasn't been able to conceive because of his use and that was Dave Tate and he was on for 17 years at abusive doses.
its an accepted FACT in the medical community that steroids CAN and WILL impact fertility in some men.
THe urologist who treated my infertility from steroids said its very common. And even the fertility clinic I initially went to said they always know when a big guy walks in with low/no sperm that he probably uses steroids.
Its really not an opinion. Some people however, can maintain FULL spermatogenesis despite severely suppressed LH and FSH levels. Additionally, many modern day juicers (esp knowlegeable bros on the boards), use ancillaries like HCG while on, or at least intermittently. HCG use can offset these effects for some