Time to pregnancy and semen parameters: a cross-sectional study among fertile couples from four European cities

Remy Slama, Florence Eustache, B. Ducot, Tina Kold Jensen, Niels Jørgensen, Antero Horte, S. Irvine, J. Suominen, A.G. Andersen, J. Auger, Matti Vierula, J. Toppari, Anders Nyboe Andersen, Niels Keiding, Niels Erik Skakkebæk, Alfred Spira, P. Jouannet