TOPICS: Y chromosome, XXY genotype, testicular atrophy, hypogonadism, seminiferous tubules, leydig cells, testosterone, luteinizing hormones (LH), sertoli cells, inhibin B, follicle stimulating hormone (FSH), intellectual disability, 2 X chromosomes, barr body, eunuchoid body shape, tall, long extremities, female hair distribution, gynecomastia