Gunter Dorner plotted the date of birth of 856 gay men from East Berlin and five other cities in East Germany (Dorner et al., 1980). Figure 11.1 shows a steep rise in birth rate frequency, starting in about 1939, reaching a marked peak in 1945, then falling back by about 1950. Dorner saw this as confirming his theory, based on animal research, that stress changed the mother's hormone balance, which could cause partial feminisation of the unborn male, and change his sexual orientation (SO). And what could be more stressful than heavy bombing by the British and American air forces, then invasion by the Russian Army?

Homosexual behaviour is permitted – indeed, on occasion obligatory – in 49 of 76 non-Western societies recorded (Ford and Beach, 1952), so societies that forbade it, as Britain and the USA did until quite recently, are in the minority. Britain and the USA are more liberal when it comes to adultery, which is, or was, forbidden in most societies, and punishable by death in many. Only one prohibition is universal; no society, with the oft-noted exception of the ancient Egyptian royal family, permits incest. Homosexual behaviour between males was illegal in Britain between 1885 and 1968. It was also regarded as a psychiatric illness; Quentin Crisp records in his memoirs being given a medical certificate declaring him unfit for military service in World War II, because he was ‘suffering’ from sexual perversion. Homosexual behaviour was nominally forbidden in the US armed services until September 2011, but has otherwise become acceptable in Britain and the USA. Homosexuality was officially ‘demedicalised’ and struck off the list of psychiatric diagnoses in the USA in 1974. Discrimination on grounds of sexual orientation is now illegal in the UK but not, surprisingly, in the USA.