I saw this a day or two late, but the geneticist Steve Jones asserts that human evolution has pretty much ground to a halt. The Times (UK) has the story . The summary of why he thinks this is the case: a big drop in the 'old guy with much younger girl' case. Fathers in their 20s have accumulated far fewer genetic mutations than fathers in their 50s..and so fewer mutations are conferred to the child. The lower mutation rate (on average) would ostensibly lead to a slower pace of evolution.
Steve Jones is the author of a pretty good evolution-focused book that I read several years ago and would recommend: Almost Like A Whale. That is the title of the UK version of the book (the version I have), but the US version is instead called Darwin's Ghost: The Origin of Species Updated .