The social characteristics of 809 couples attending a sex preselection clinic have been studied. Their ethnic origins were: Indian 57.8%, European 32.0%, Chinese 3.6% and others 6.8%. The average number of boys and girls per family was 0.09 and 2.70 respectively for couples wanting a boy, and 2.46 and 0.14 for those wanting a girl. The average age of the wives was 34.0 years. These figures were not significantly different in any ethnic subgroup. Out of all the couples, 80.6% stated that they would have had another baby even had sex preselection not been on offer; 37.5% of the couples interviewed have been treated so far. The figures among those treated are substantially the same as those for the whole group. Asian and Middle Eastern couples overwhelmingly wanted boys, whereas European couples showed a slight preference for girls. These results suggest that, given certain guidelines, sex selection is unlikely to lead to a serious distortion of the sex ratio in Britain and other Western societies, but may need careful monitoring in other parts of the world.

Avoiding activities posing bodily threat is adaptive. However, spreading of avoidance to safe activities may cause functional disability in people with chronic pain. We investigated whether costly pain-related avoidance would generalize from one activity to another on the basis of real-life categorical knowledge in 40 pain-free people (30 female; mean age = 25 years; university students and public of Maastricht, The Netherlands). In a computer task, participants moved a joystick to complete activities from two categories (gardening and cleaning). During activities from the avoidance category, pain could be avoided at the cost of task efficiency by deviating from a short, pain-associated joystick movement. Activities from the safe category were never painful. Subsequently, we tested generalization of avoidance to novel pain-free activities from both categories. Participants generalized avoidance to novel activities from the avoidance category despite the novel activities not being paired with pain and despite avoidance costs, suggesting that costly (pain-related) avoidance generalizes from one activity to another on the basis of category knowledge and can thus be wide reaching, creating detrimental consequences.