In a full page ad in The New York Tinzes Book Review for Sex & Destiny: Tbe Politics of Human Fertility by Germaine Greer (Harper & Row; New York) a cer­tain Fay Weldon’s words from a piece in the London Times are quoted in type that’s 1/2-inch high: “One of the most important books to be written this century.” Now, what some people in London may know–something that fewer here in the colonies are aware of–is that Ms. Greer was once a comedian who worked with some of those men who are now best known under the encompassing sobriquet “Monty Python.” Perhaps, unbeknownst to the readers of ads in the NYTBR, Fay Weldon’s blurb is actually part of a comedy sketch. After all, the title of Ms. Greer’s book does sound rather imposing, doesn’t it? And its bulk–541 pages fat–is enough to make one imagine that this is a scholarly tome, enough to make one overlook the fact that the dust jacket photo shows the author not in professorial robes, but bib overalls. But when all of that is penetrated, when one gets to the heart of the matter, then one discovers that Ms. Greer’s point is that many people in Western industrialized countries–especially those who die for their Sunday Times–subscribe to an attitude towared children noted by that great American philosopher W. C. Fields.