A 2014 study by scientists at Karlstad university in Sweden found that baby boys exposed to phthalates prenataly were born with smaller penises and anogenital gaps http://ehp.niehs.nih.gov/wp-content/uploads/advpub/2014/10/ehp.1408163.acco.pdf And it’s not just baby penises that could be affected – a 2012 study found a 2cm average reduction in penis size from grandfather to grandson in the 20th century – correlating with the advent of plastic. And plastic is also a suspect in the fall off in human sperm count first reported by Carlsen et al in 1992. Plastic has not been irrefutably confirmed as the culprit, however both correlate with the advent of heavy plastic use in the sample communities analysed. Now how on earth could plastic mean smaller penises you ask? It’s because virtually all commercial plastics leach synthetic oestrogen, which the body mistakes for and reacts to as natural oestrogen, so men are feminised. The flip side of this would be earlier onset of puberty in girls. And this has in fact been found to be the case in a 1997 paper by Marcia Herman-Giddens. This does not mean plastic definitely did it, but something did and plastic is one explanation that fits. This is a great article: http://blogs.plos.org/neuroanthropology/2015/04/19/plastics-and-human-evolution/