Lisa Schuman, LCSW
September 10, 2026
Families who use donor eggs or donor sperm often wonder about the other children conceived with help from the same donor. Donor sibling relationships are as unique as the people who share them, and parents tend to ask the same questions: should we reach out, when, and how?
If you are weighing those questions for your own family, this guide explains what donor-related siblings are, how families find each other, what research shows about these relationships, and what to think through before making contact. Donor embryo connections tend to differ significantly, so the focus here is on families who have used donor eggs or sperm.
The short answer
Donor siblings are people conceived with the same egg or sperm donor who grow up in different families.
Many families connect through the Donor Sibling Registry, their donor program or DNA testing. There is no single right time to reach out, and feelings about these connections often change as children grow.
What are donor siblings?
Donor siblings, or donor-related siblings, are children conceived with gametes from the same donor and raised by different parents. Because they share one genetic parent, they are usually genetic half siblings.
With donor eggs, how many families share a donor depends on the program. In a fresh donor cycle, one set of intended parents receives the eggs from that retrieval, and siblings born from those embryos grow up together as full siblings. Donors may complete more than one cycle, though, and eggs from a frozen egg bank can help more than one family, so donor-related siblings in other homes are possible. Some parents plan for this by choosing a sibling cycle with the same donor.
| Term | What it means |
|---|---|
| Donor sibling | A person conceived with the same donor, raised in a different family |
| Full sibling | Shares both genetic parents, such as two children born from embryos created in the same cycle |
| Half sibling | Shares one genetic parent, which is typical for donor-related siblings in different families |
| Donor sibling group | Families who share a donor and choose to stay in contact |
How many donor siblings can a child have?
The number of donor siblings a child can have varies, and professional guidelines set suggested limits. The American Society for Reproductive Medicine (ASRM) recommends that egg donors be limited to six treatment cycles, and it suggests no more than 25 births per sperm donor in a population of 800,000.1
Sperm donors can help many more families than egg donors, so children conceived with donor sperm are more likely to have a large donor sibling group. Donor egg families usually share a donor with fewer families.
Should you connect with your child's donor siblings?
Whether to connect is a personal decision, and families reach different answers for good reasons. Parents are often curious about donor-related siblings for medical or emotional reasons, such as sharing health updates or giving their child a chance to know people who share part of their genetic story.
Many egg banks, sperm banks and agencies write contracts that keep donors nonidentified until a child turns 18, and parents often want to respect that informal rule. However, there is no such "rule" for genetically related siblings, and we have found that many donors and genetically related siblings feel comfortable with contact.
Anonymity also works differently today. ASRM notes that "maintaining anonymity of parties cannot be guaranteed" now that commercial genetic testing and social media make it easier to identify genetic relatives.2 Children who know their story from an early age are better prepared if a match appears unexpectedly, which is one reason experts encourage talking to your child about donor conception early.
How do families find donor-related siblings?
Most families find donor-related siblings through a registry, their donor program, or DNA testing. Each option offers a different level of control over timing and privacy.
| Option | How it works | Points to consider |
|---|---|---|
| Donor Sibling Registry | A nonprofit registry where families search by donor number and clinic or bank to make mutually desired contact | Both sides choose to join, so contact is by consent |
| Your egg bank, sperm bank or agency | Some programs offer sibling contact options or pass messages between families | Options depend on your program and your donor agreement |
| Consumer DNA testing | Genetic relatives who have tested with the same company can appear as matches | Results are permanent and can reveal relatives who did not expect contact |
| Online groups for donor-conceived families | Parents connect through groups organized around a donor or a program | Privacy settings and group rules vary |
The Donor Sibling Registry was founded in 2000 to help people conceived through sperm, egg or embryo donation make mutually desired contact with others who share their genetic ties.3 It is a 501(c)(3) nonprofit and one of the most widely used places to start.
How do donor sibling relationships change over time?
Donor sibling relationships often shift as children grow, move and form their own opinions. Connections with siblings can feel simpler than relationships with donors, yet donor-conceived people describe a wide range of feelings about both, from strong interest to none at all. Several children in the same family with the same donor may feel very differently.
In the book Random Families, sociologists Rosanna Hertz and Margaret K. Nelson describe families who share a sperm donor and found that they differed in how they connected, why they connected, how deep those relationships became, and how the relationships changed over time.4 Some connections felt close before drifting apart. Adolescence and distance can change these relationships, and temperament, neurodiversity, culture and religion affect how people relate to one another.
A study of more than 2,000 parents and 400 offspring who share sperm donors found that offspring were more likely than parents to see donor siblings as part of their extended family.5 Your child may come to see these connections differently than you do.
Kiara Rae Schuh, author of Chosen Family, spoke on the Building Your Family podcast about wanting to connect with her donor-related siblings and her donor, while her brother has no interest in connecting with genetic relatives. Her experience is a good reminder that siblings in the same family can feel very differently about these connections, and that those feelings can shift over time.
What should you think about before reaching out?
Before reaching out, think about your child's age and wishes, what your donor agreement allows, and how much contact your family wants. A few questions help:
- Does your child know their story? Contact tends to go more smoothly when a child already understands how they were conceived.
- What does your child want? Some donor-conceived people wish their parents had introduced them to donor siblings early, while others feel the choice should be theirs to make.
- What did your donor agreement say? Nonidentified, identified and Open ID donations set different expectations, which our guide to anonymous vs. open egg donation explains.
- How much contact feels right? Families can start with messages or photos and decide together whether to meet.
- Do you want support? A counselor who works with donor conception families can help you plan conversations with your child and with other families.
Some patterns do show up. Many only children appreciate meeting donor-related siblings, and donor-conceived people often enjoy meeting others with similar backgrounds. Weighing the pros and cons with the research available, while considering your children's personalities and developmental stages, will help you choose what fits your family.
If you are still choosing a donor, the Donor Nexus Frozen Egg Bank offers both Non-ID and Open ID donors, and our donor egg programs page explains how fresh matching and frozen eggs differ.
If you're exploring donor eggs, our guides to using donor eggs, how our egg donor agency works and our frozen donor egg bank walk through each path, and you can create an account to search the egg donor database whenever you're ready.
Frequently asked questions
What are donor siblings?
Donor siblings, also called donor-related siblings, are people conceived with eggs or sperm from the same donor. They are genetic half siblings when they have different other parents, and they usually grow up in separate families.
How do I find my child's donor siblings?
Families most often connect through the Donor Sibling Registry, through contact options offered by their egg bank, sperm bank or agency, or through consumer DNA testing. Some families also meet through online groups for donor-conceived families.
Should I contact my child's donor siblings before age 18?
There is no rule that says you must wait. Many families wait until children are 18 to contact a donor, but some connect with donor-related siblings earlier, often when both families agree and the children already know their story.
How many donor siblings can a child have?
The number varies by donor and program, and ASRM guidance recommends limiting egg donors to six cycles and suggests no more than 25 births per sperm donor in a population of 800,000.
Can a DNA test reveal donor siblings?
Yes, if a donor sibling or a relative of the donor has tested with the same company, a consumer DNA test can show a genetic match. That is one reason ASRM says donor anonymity cannot be guaranteed.
Sources
- Practice Committee of the American Society for Reproductive Medicine. Gamete and embryo donation guidance. Fertility and Sterility. 2024;122:799-813. asrm.org
- Ethics Committee of the American Society for Reproductive Medicine. Interests, obligations, and rights in gamete and embryo donation: an Ethics Committee opinion. Fertility and Sterility. 2019;111:664-670. asrm.org
- Donor Sibling Registry. History and mission. donorsiblingregistry.com
- Hertz R, Nelson MK. Random Families: Genetic Strangers, Sperm Donor Siblings, and the Creation of New Kin. Oxford University Press; 2018. academic.oup.com
- Hertz R, Nelson MK, Kramer W. Donor sibling networks as a vehicle for expanding kinship: a replication and extension. Journal of Family Issues. 2017;38(2):248-284. journals.sagepub.com
Disclaimer
This article is general information for donor-conceived families and is not medical, psychological or legal advice. Talk with a counselor who specializes in donor conception, and an attorney about your donor agreement, before making contact decisions.
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Lisa Schuman, LCSW
Lisa Schuman, LCSW is a licensed clinical social worker who has specialized in reproductive mental health and family building for 30 years. She is the founder and director of The Center for Family Building, and…
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