Shapely centrefolds? Temporal change in body measures: trend analysis.

was higher than that expected by chance. Distinguishing features that are present in newborns' faces allow adults to identify the babies' sex, but these cues are subtle and easily missed or inconsistent. Accuracy increases with exposure to newborns, as seen with the nurses in our study. Perhaps people who have more contact with babies are more able to see differences between babies. Preconceptions relating to hairiness may influence people's assumption of neonates' sex. Our sample size did not allow us to determine whether girls really are hairier than boys. It could be concluded that the major clue to a baby's sex is its hairiness; perhaps experienced observers subconsciously take note of hairiness and so are better at identifying sex. Overall, the observers in our study could identify the babies' sex from their faces—but why couldn't the paediatricians get it right? We thank the participants and staff at Guy's Hospital, especially Grenville Fox, Judy Rissik, and Richard Morris for support, inspiration, and advice. Contributors: JECR managed the study. Both authors collected and analysed the data and wrote the paper. Body mass index (weight (kg)/(height (m) 2) and waist-:hip ratio in women are linked to fertility, endocrine status, risk of major diseases, and longevity. 1–3 Health related optimums for body mass index (20 or slightly lower 2) and waist:hip ratio (0.7 or slightly lower 3) are also maximally sexually attractive to men. 1 3 According to evolutionary research, these attractiveness opti-mums reflect evolved optimal design and thus should not be subject to temporal change. 3 This assumption is not consonant with the decline in the optimally attractive body mass index that has occurred in the past few decades, as exemplified by fashion models depicted in the media. With increases in the incidence of eating disorders in the general population of women, this decline is a cause for concern. 4 5 In contrast , Singh has reported evidence for the temporal stability of the maximally attractive waist:hip ratio, on the basis of analysis of the waist:hip ratios of centrefold models in Playboy. 3 However, Singh based this conclusion , as is the case for other studies pertaining to body measurements of Playboy centrefolds, 4 on a partial sample. We looked at the trends in Playboy centrefold models' body measurements by analysing 577 consecutive monthly issues, from the magazine's inception in December 1953 to December 2001. We extracted cen-trefolds' anthropometric data: height, weight, and …