I don't think we have an implied_infidelity tag, but given the boy in front's watermelon, ponytail, and the artist's history of pairing him with Asuka, Kaji Ryouji might be implied to be the father for at least one of these two.

Shinjidude said in comment #2582106:

I don't think we have an implied_infidelity tag[...]

I believe that tag's called implied cheating (relationship) around these parts.

Alanis, killed by a mother named Asuka