Objective-To develop and evaluate a model of health care for HIV positive patients involving specialist, hospital based teams and primary health care teams.Design-One year retrospective and 21/2 year prospective study.Setting-Two hospitals in west London and 88 general practitioners in 72 general practices.

While a seasonal effect on maternal hCG was demonstrated our data does not suggest this to be the sole cause for cryptorchidism or hypospadias or to account for the observation that both have a seasonal frequency.