Human gonadal stromal cells are derived from testes that have been dissociated into a single cell suspension. Human gonadal stromal cells are from a single donor. These cells enable researchers to investigate reproduction, stem cells, and disease in vitro. In addition, these cells may be used for developmental studies. Robertsonian translocation (RTL) is a common form of chromosomal rearrangement that in humans that occurs in the five acrocentric chromosome pairs. People with RTL have only 45 chromosomes in their cells with all essential genetic material present. They appear normal, however their children may be either normal and carry the fusion chromosome, or they may inherit a missing or extra long arm of an acrocentric chromosome causing disorders such as Down syndrome.