The Wages of Sin?

Curiously, in the opening and closing scenes of King Lear, there is mention of the begetting of Edmund.  It is passed off as a joke, initially, but becomes quite bitter by the end.

In 1.1, Gloucester says to Kent (re Edmund, who is present):

Though this knave came something
saucily to the world before he was sent for, yet was
his mother fair, there was good sport at his making,
and the whoreson must be acknowledged.

I would note this is structured as prose (not iambic pentameter) and is uttered in Edmund's presence, without any regard for the young man's feelings.

Then in 5.3, Edgar says to Edmund (re Gloucester, who is absent/dead):

The gods are just, and of our pleasant vices
Make instruments to plague us.
The dark and vicious place where thee he got
Cost him his eyes.

Here, we have iambic pentameter interspersed with significantly shorter lines.  I find it natural to read both of the short lines with just two stresses, though the first one could – and perhaps should – be read as iambic trimeter, to make the final line all the more jarring: Cost him his eyes.

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Side Note: I don't think Edmund ever claims that he'd have been what he is had he been begotten (or at least born) in wedlock, but he does disclaim any astral influence, noting "I should have been that I am, had the maidenliest star in the firmament twinkled on my bastardizing" (1.2).