**Functional Ovarian Reserve in Sickle Cell Disease** Sickle Cell Disease (SCD) is a blood disorder affecting red blood cells. This study looks at the levels of a hormone called Anti-Müllerian Hormone (AMH) in girls with SCD. AMH helps us understand ovarian reserve, which is the number of eggs a girl has. Researchers want to see if girls with SCD have different AMH levels compared to healthy girls as they grow up. They will also check if treatments and pain crises in SCD affect AMH levels. The study lasts two years and is part of a longer eight-year effort. Girls aged 10-18 with SCD or healthy girls of similar backgrounds can join. Participants will answer yearly questions about their puberty, menstrual history, and medication use. Some will give a blood sample during a clinic visit; healthy controls will give one sample during their research visit. - **Duration**: Two-year study within an eight-year project. - **Visits**: Annual questionnaires and a single blood sample. - **Eligibility**: Girls with SCD or healthy peers, aged 10-18. Participants can't join if they've had certain treatments like stem cell transplants or are pregnant.