1. Institute of Life Science (D.G., P.D.L., J.O.W., R.S.C.), College of Medicine, Swansea University, Swansea SA2 8PP, Wales, United Kingdom
2. Abertawe Bro Morgannwg University Health Board (H.T., L.J.), Singleton Hospital, Swansea SA2 8QA, United Kingdom
3. The London Women's Clinic (H.T.), Swansea SA2 8QA, United Kingdom
4. Institute of Reproductive and Developmental Biology (A.M., N.B., R.M.), Hammersmith Hospital, London, W12 0NN, United Kingdom
5. The London Women's Clinic (K.A.), London, W1G 6AP, United Kingdom