From: Rabbi Moshe Sofer
To: Rabbi Yisrael
The Chasam Sofer argues that Gittin 43a actually supports the Maharshal's view that a minority of treifos can reproduce, contrary to the Pri Chadash's proof. The use of the word 'heirs' in the braisa implies at least a theoretical possibility of offspring, but an elaborate chain of improbabilities explains why Rava says the treifah is 'worthy of heirs but has none.' Any son born under such circumstances would be fully legitimate due to the wife's chezkas kashrus.
Source: Shu"t Chasam Sofer EH II §149