A study of French fertility using differential and parity based analysis: is the recently seen downturn in French fertility happening for all women or just certain subpopulations? and for all parities? Among the other themes covered by the subject, experiences of male fertility and paternity will be observed to establish a snapshot of their experiences and diverse family situations. Also the impact on family situations of multipartner fertility - more and more frequent as relationship trajectories become more unstable and more complex - will be studied. Equally, there will be a focus upon the fertility of couples following a stillbirth, are there factors which encourage or hinder the parents to add to their family size? Finally, the reliability of birth parity data in the French birth registration system will be evaluated.