[citation needed] Born in Wiltshire, England in 1944, Robin Baker grew up in the small village of Manningford Bruce in the Vale of Pewsey.

His thesis investigated the evolution of the migratory habit in butterflies and applied principles of behavioural ecology and evolutionary biology to the insect migration.

[11] Noticing that sperm in a mixed sample tends to clump together—making it less mobile—and to have a high mortality rate, reproductive biologist Robin Baker, formerly of the University of Manchester, proposed about a decade ago[when?]

To test this idea, reproductive biologist Harry Moore and evolutionary ecologist Tim Birkhead of the University of Sheffield mixed sperm samples from 15 men in various combinations and checked for how the cells moved, clumped together, or developed abnormal shapes.

The findings are "the nail in the coffin for the kamikaze hypothesis," says Michael Bedford, a reproductive biologist at Cornell University's Weill Medical Center in New York City.

This figure was later debunked, because studies which rely on a data set consisting of men who have requested paternity tests are strongly sample biased toward those who have a reason to have suspicions.

[17] "Media and popular scientific literature often claim that many alleged fathers are being cuckolded into raising children that biologically are not their own," said Maarten Larmuseau of KU Leuven in Belgium.

The observed low cuckoldry rates in contemporary and past human populations challenge clearly the well-known idea that women routinely 'shop around' for good genes by engaging in extra-pair copulations to obtain genetic benefits for their children," Larmuseau said.