Our study hypotheses were as follows: (1) Loss of testicular parenchyma due to surgery is associated with decreased 25OHD serum level, (2) loss of both testicles will cause even lower 25OHD levels, (3) 25OHD deficiency will increase with time interval from testicular loss, (4) impaired spermatogenesis evidenced by increased levels of follicle stimulating hormone (FSH) is associated with 25OHD deficiency. The gene discussed is BRD2; the disease is hyperinsulinemic hypoglycemia, familial, 4.