That's completely untrue. Canon law has always recognized children of a putative marriage entered into in good faith as legitimate. In the current (1983) CIC, the concepts of "legitimacy" and "illegitimacy" don't even exist.
Thank you for clearing that up for me. I read a question from a woman very upset about that and afraid to get one on the Catholic Community Forum a while back.
I suppose they can also go to a liberal Catholic church and take communion anyway too, but I don't think that's the kind of ideal we're going for in this discussion.