I called that horrible retconning, but I was actually shot down by the "If They Haven't Said It, You Don't Know It" Crowd.
A couple of months back I argued on another board about Chief and his kid. I was told that they've never stated that male Cylons can't father children by humans -- only that female Cylons can't get pregnant.
We know female Cylons can get pregnant - Athena had Hera, and Caprica Six is pregnant.
The issue was that the Cylons couldn't conceive together. They thought that a human might be needed, and so the Eight "recruited" Helo.
I called that horrible retconning, but I was actually shot down by the "If They Haven't Said It, You Don't Know It" Crowd.
I think that's actually a pretty good rule of thumb, actually.