I found the use of this phrase very interesting. My inference from previous reading was that a "monstrous birth" was a phrase from a much earlier period in history, used to describe still-births or severely deformed babies that died shortly after birth. From my understanding, they were seen as a punishment from God for some moral failing on the part of the mother. This usage implies that a monstrous birth is someone who has moral failings. I wonder whether this is the true version of the "monstrous birth" for the present age.

[Side note: I tried finding the etymology, but struggled to do so, perhaps because it is a phrase rather than a single term.]