Finasteride (a synthetic 5-alpha-reductase inhibitor) is used for the treatment of male pattern baldness and benign prostatic hyperplasia. There have been few reports on pregnancy outcomes after paternal exposure to finasteride either prior to or during pregnancy. Nineteen cases with documented paternal exposure to finasteride either prior to or during pregnancy were identified through the Korean Motherisk program. Detailed patient histories were obtained and each patient was followed from pregnancy through abortion or delivery. Of the 19 patients, 13 (68.4%) gave birth to normal full-term babies. The other six cases (31.6%) resulted in either spontaneous (n=3) or artificial (n=3) abortions. These results are consistent with previous animal studies demonstrating an increase in adverse outcomes with paternal exposure to finasteride.