Jack Wilkinson1, Antonio Pellicer2, Craig Niederberger3. 1. Centre for Biostatistics, University of Manchester, Manchester, United Kingdom. 2. Instituto Valenciano de Infertilidad (IVI), Rome, Italy; Instituto de Investigación Sanitaria La Fe, Valencia, Spain. 3. Department of Urology, University of Illinois at Chicago College of Medicine, Chicago, Illinois; Department of Bioengineering, University of Illinois at Chicago College of Engineering, Chicago, Illinois.