<qa>  What is the collection of parental DNA proposed when feasable for genetic studies?Clinical and paraclinical data, and biological samples plasma, serum, DNA, RNA, cell blood, for persons undergoing bariatric surgery specific consent: samples of liver and adipocytes will be collected and stored during the follow-up visits. These visits take place at inclusion, at 6 months, twelve months and every year for ten years. The collection of parental DNA will be proposed when feasable for genetic studies. 