they said, with singleton IVF babies, there was more likelihood of a premature birth or a clinically low birth weight. It is known that this can sometimes cause health and developmental problems as a child grows up. The panel also found that IVF babies are also twice as likely to die during birth, or soon after. The evidence also suggested that IVF babies are at greater risk of being born with some rare disorders caused by a failure of 'genetic imprinting', such as Beckwith-Wiedemann syndrome. Some scientists think this may be due to the conditions in which embryos are kept in the laboratory, before being transferred to the womb.