Who's the father of the child?

Thomas poses the question of fatherhood (twice) to Georg (would he know?) at the birthday party. No reaction from Judith. When Judith later admits that "some years ago" she had an affair with Georg, she could have settled the issue. Replacing "some years ago" with something specific, would place the affair before/around/after the child was conceived. Judith could even have suggested that she and Georg used some means of anti-conception.

Since she keeps completely silent about the issue, I think that the message we're supposed to pick-up is that Georg may well be the father.

I assume that when Judith starts her confession "Es ist war ..." refers to her having slept with Georg, not Georg being the father of the child.