Donor-conceived people discover 30-600 half-siblings through DNA tests, with no legal framework to limit donor offspring counts

A woman named Eve Wiley discovered through DNA testing that she had 62 half-siblings from the same sperm donor. Another case documented by CBC involved a man who discovered approximately 600 biological children fathered by a single fertility doctor, B.P. Wiesner, who secretly used his own sperm. These are not outliers. The Donor Sibling Registry has connected over 25,000 donor-conceived people with half-siblings and donors since 2000. In a 2020 survey by We Are Donor Conceived, 78% of respondents had successfully identified their donor via DNA testing, and 70% had found at least one donor sibling. The immediate pain is identity shock: you take a DNA test expecting ethnicity percentages, and instead you discover that the man who raised you is not your biological father, that your parents lied to you for decades, and that you have dozens of half-siblings you never knew existed. But the deeper problem is medical: many donor-conceived people have developed hereditary conditions — cardiac defects, rare cancers, genetic disorders — that could have been caught earlier if they had known their biological father's medical history. When one donor fathers 50+ children, a single carrier of a recessive genetic disorder can create a cluster of affected offspring across multiple families who have no idea they share a risk. This persists because the US has no federal law limiting how many offspring a single donor can produce. The American Society for Reproductive Medicine recommends a limit of 25 families per donor per population of 800,000, but this is a guideline, not a law, and sperm banks self-report with no verification. Donor anonymity was the industry's selling point for decades, and even though consumer DNA testing has made anonymity impossible in practice, the legal and commercial infrastructure still operates as if anonymity exists. Sperm banks have no obligation to notify donor-conceived people about half-siblings or update medical histories when donors develop conditions later in life.