Smoking habits of parents and male: female ratio in spermatozoa and preimplantation embryos

BACKGROUND Previous observations have addressed a decreased male:female ratio associated with smoking. Our aim was to assess whether this effect is observed at the spermatozoa or at the early embryo development. METHODS We retrospectively assessed smoking intake habits of 56 couples included in our preimplantation genetic diagnosis (PGD) program. Three groups were established according to male or female cigarette consumption per day: non-smokers, smokers (1-19 cigarettes per day) and heavy smokers (> or =20 cigarettes per day). Fluorescence in-situ hybridization (FISH) was performed on ejaculated sperm samples to analyse chromosomes X and Y. On day 3, embryos were also analysed. Additionall…