A married couple exchanges letters. Wife Anne is in U.S.A, while husband Alan, a biology scientist, tries to free Columbian people of parasitic infections. The title refers to a technique which controls the population of screwflies by sterilizing males which will compete with fertile males. Humans are treated the same way, here. It starts with murders of females in U.S., spreading cults of „The Sons of Adam“, mass hysteria and delusions. Things are getting worse, and in the end really dark.
The novelette has been adapted 2006 into a TV movie as part of „Masters of Horror“. It explores a broad range of typical topics like love, violance against females, or religion. I found it to be a bit predictible, giving away too much too soon. The ending is a kind of teachery „gotcha“ which I didn’t like.