Some clinical studies require the use of a placebo or control group in order to know if a drug or treatment is effective. The placebos are not identifiable by either the participant or the research team, and are randomly assigned to study participants. In addition, some clinical studies will allow you to benefit from various additional tests (e.g. blood tests, ultrasound, electrocardiogram, mammography, ovarian reserve, current health and medical history questionnaires...) as well as physical and/or gynecological examinations at no cost.