The last major study of psychological effects was completed on small, primarily middle class samples, over a decade ago when vasectomy (vas) was rare and social context presumably different in the U.S. The authors concluded, "The negative side effects...are already largely disguised and non-obvious...vasectomy tends to have a more favorable reputation among some...than it deserves". The present study begins with approximately 350 men who have decided on vas, and 230 wives of these men, mostly people coming to vasectomy clinics. These individuals and appropriate controls are given, some time before vas, standard psychological tests (MMPI, CPI, figure drawings), a Life Situations checklist (Holmes-Rahe-Paykel, adapted), and specially devised questions relating to vas attitudes and expectations and other relevant materials. Approximately one year later all Ss are re-contacted for restudy. It is hypothesized that a small minority of men and wives will show negative pre-post changes as compared to controls. Of greater interest are fine-grain analyses designed to help predict which individuals, if any, experience positive or negative effects. Empirical evidence will show, after cross-validation, whether short-form screening tests can predict in advance the out-comes of vas, with some validity. A small group of parallel couples where the woman is sterilized are also being studied under this budget.