Even if we relax some of the assumptions, ART in its present form cannot make up for all births lost by the natural decline of fertility after age 35 years.

The late 20th century trend to delay birth of the first child until the age at which female fecundity or reproductive capacity is lower has increased the incidence of age-related infertility. The trend and its consequences have also stimulated interest in the possible factors in the female and the male that may contribute to the decline in fecundity with age; in the means that exist to predict fecundity; and in the consequences for pregnancy and childbirth. In the female, the number of oocytes decreases with age until the menopause. Oocyte quality also diminishes, due in part to increased aneuploidy because of factors such as changes in spindle integrity. Although older male age affects the likelihood of conception, abnormalities in sperm chromosomes and in some components of the semen analysis are less important than the frequency of intercourse. Age is as accurate as any other predictor of conception with assisted reproductive technology. The decline in fecundity becomes clinically relevant when women reach their mid-30s, when even assisted reproduction treatment cannot compensate for the decline in fecundity associated with delaying attempts at conceiving. Pregnancies among women aged >40 years are associated with more non-severe complications, more premature births, more congenital malformations and more interventions at birth.

No external funding was either sought or obtained for this study. There are no conflicts of interest to be declared.

Public health interventions that are synergistic with trends in social norms are likely to be more effective than those that run counter to them. In France, sexual health and HIV prevention policies aimed at harm limitation appear to have chimed with secular trends. The evidence of greater diversification of sexual practices offers potential to increase the range of safer sex messages used in public health interventions.