|Writer and producer Tom Fontana.|
It's the very first script he wrote for television, back in 1982, for St. Elsewhere's third episode, "Down's Syndrome". He had previously been a playwright, and had never written television before this. The page linked below explains the background behind the episode, including how his portrayal of Down's Syndrome drew criticism from George Will, who has a Down's child.
What mighty oaks from tiny acorns grow. Here's the link:
If you recall the episode, you may notice a scene that was excised from the version that aired. In it, Andrew Rhinehardt's parents tell the story of how their terrorist-bomber son lost his way. IMHO, they made the right choice. What was left in--a brief comment about how he fell in with political radicals--was enough to paint the picture.