In the future any more sophisticated investigative techniques may uncover causes of male
infertility not diagnosable by current methods. Study of receptors on sperm may reveal abnormalities that preclude sperm-zona or sperm-oocyte interaction. Assessment of the role of ABP. the androgen binding protein, and the process of spermatogenesis and maturation may uncover specific disorders currently unknown. The genetic analysis of sperm may make it possible to be selective for "good" sperm. Finally, with micromanipulation it is now possible to place a single sperm within an egg. Pregnancies have been achieved by micromanipulation with men who have sperm counts less than 100,000/mL with zero motility and no normal forms (see Chapter 31).