The purpose of this study is to learn what factors influence adolescent girls' decisions regarding testing for carrier status of X-Linked Severe Combined Immunodeficiency (XSCID). It will provide information about how healthy relatives feel about whether they could be XSCID carriers, whether carrier testing should be pursued, and, if so, at what age. Commonly known as "Bubble Boy Disease," XSCID is a rare, life-threatening immune system disorder that affects only males, but females who carry the gene mutation can pass the disease to their male children.