Selecting a donor, whether for sperm, eggs, or a bone marrow transplant, comes down to matching medical safety, genetic compatibility, and personal priorities. The process differs depending on the type of donor, but every path involves standardized screening that protects both you and any future child or transplant recipient. Here’s how to navigate each step.
Decide Between Known and Anonymous Donors
For reproductive donors (sperm or eggs), your first major choice is whether to use someone you know or select from an anonymous donor through a bank or agency. Each path carries different practical and legal weight.
A known donor, such as a friend or family member, gives you direct access to their full health history and personality. But it also introduces legal complexity. Every state has its own laws governing sperm and egg donation, who qualifies as a legal parent, and what paperwork must be in place before conception. Without a formal legal agreement drafted by an attorney experienced in assisted reproduction, a known donor could later claim parental rights, or you could face challenges establishing your own. Legal fees for these agreements typically run several hundred to a few thousand dollars.
An anonymous donor, selected through a cryobank or egg donor agency, comes with built-in legal protections. The clinic and agency handle contracts, and donors relinquish parental claims as part of the process. You’ll choose from detailed profiles that include physical characteristics, education, health history, and sometimes audio interviews or childhood photos. Many banks now offer “open ID” or “identity release” donors, meaning the child can request the donor’s identity after turning 18.
What Medical Screening Covers
The FDA requires all reproductive tissue donors to be tested for HIV (types 1 and 2), hepatitis B, hepatitis C, and syphilis. Living donors must also be screened for West Nile virus. Reproductive donors specifically are tested for chlamydia and gonorrhea using tests designed to detect these infections even in people with no symptoms.
These are federal minimums. Most reputable cryobanks and egg donor agencies go further, screening for cytomegalovirus (CMV), checking hormone levels, and performing physical exams. If you’re using a known donor, you’ll need to arrange this testing through your fertility clinic, since it won’t happen automatically.
Genetic Carrier Screening
Expanded carrier screening is one of the most important steps in selecting a reproductive donor. These panels test for conditions that a carrier shows no signs of but could pass to a child if both biological parents carry the same gene variant. The goal is to identify risky matches before conception.
Modern panels screen for dozens to hundreds of conditions. To be included on a panel, a condition generally must have a carrier frequency of at least 1 in 100, affect quality of life or cause cognitive or physical impairment, require medical or surgical treatment, and show up early in life rather than in adulthood. Cystic fibrosis, sickle cell disease, spinal muscular atrophy, and Tay-Sachs disease are among the most commonly screened.
If you’re selecting from a sperm or egg bank, the donor’s carrier status is typically listed in their profile. Your clinic can then compare your own carrier screening results to the donor’s. Two carriers of the same recessive condition have a 25% chance of having an affected child, so most clinics will flag that pairing and recommend choosing a different donor.
Sperm Donor Quality Standards
Not everyone who wants to donate sperm qualifies. Cryobanks apply stricter standards than general fertility benchmarks because sperm must survive freezing and thawing. The typical minimum criteria require a semen volume above 2 mL, sperm concentration above 50 million motile sperm per milliliter, and more than 50% of sperm moving actively in a purposeful direction. After freezing and thawing, at least 50% of that initial motility must remain.
These numbers are significantly higher than what’s considered “normal” for the average man. That’s intentional: the freeze-thaw process kills a portion of sperm cells, so starting with a higher count ensures enough viable sperm remain for insemination or IVF. When reviewing a donor’s profile, look for post-thaw motility data, not just the pre-freeze numbers.
Egg Donor Age and Success Rates
Age is the single strongest predictor of egg quality. Most programs recruit egg donors between the ages of 21 and 32. Younger eggs have fewer chromosomal abnormalities, which translates directly into higher pregnancy and live birth rates.
The difference is dramatic for recipients over 40. Women aged 40 to 45 using their own eggs have a live birth rate of roughly 5 to 10% per IVF cycle. With donor eggs from a younger woman, that rate jumps to 40 to 45%. Even for women over 45, donor eggs yield live birth rates of 30 to 35%, compared to less than 5% with their own. The recipient’s age matters far less when using donor eggs because it’s the egg’s chromosomal health, not the uterus, that drives most age-related fertility decline.
Health and Family History
Donor profiles include a detailed family medical history, typically covering three generations. You’re looking for patterns: multiple relatives with the same type of cancer, early-onset heart disease, autoimmune conditions, or psychiatric illness across generations. No family history is perfect, but clustering of serious conditions is a reasonable reason to choose a different donor.
The FDA’s exclusion criteria for donors focus primarily on communicable diseases rather than broad family health. One notable exception is Creutzfeldt-Jakob disease (CJD), a rare and fatal brain condition. A donor with a blood relative diagnosed with CJD is disqualified unless genetic testing confirms they don’t carry the associated mutation. Beyond federal rules, individual clinics and banks set their own thresholds for family history red flags, so standards vary.
Psychological Screening
Egg donors and, at many programs, sperm donors undergo a psychological evaluation before being accepted. This isn’t just a personality test. The assessment screens for substance abuse in the donor or their immediate family, history of abuse or neglect, legal history, evidence of coercion (financial or emotional pressure to donate), impaired cognitive functioning, and high-risk sexual behavior.
For egg donors, the psychological component also evaluates whether the donor fully understands the physical demands of the process: hormone injections, monitoring appointments, and a retrieval procedure. Donors who show signs of being motivated purely by compensation, without understanding or accepting the risks, are typically screened out. Compensation for egg donors should reflect the time, inconvenience, and physical demands of the process. It should never be tied to the number or quality of eggs retrieved, and donors should not be penalized financially if a cycle is canceled.
Selecting a Bone Marrow Donor
If you’re selecting a donor for a bone marrow or stem cell transplant, the process is fundamentally different. Instead of choosing from profiles, you’re searching for a biological match based on human leukocyte antigen (HLA) markers, proteins on the surface of your cells that your immune system uses to distinguish “self” from “foreign.”
Doctors look at up to 12 HLA markers on your DNA and typically need 8 to 10 of those 12 to match. With millions of possible HLA combinations in the general population, finding a match can be difficult, especially for patients from underrepresented ethnic backgrounds. Siblings have roughly a 25% chance of being a full match. When no family match exists, registries like the National Marrow Donor Program search their database of volunteer donors worldwide.
Umbilical cord blood transplants are more forgiving. Doctors may only need 4 to 6 of the 12 markers to match, because cord blood cells are immunologically immature and less likely to attack the recipient’s body. This makes cord blood a valuable option when a closely matched adult donor can’t be found.
Practical Steps for Making Your Choice
Start by narrowing donors based on medical and genetic compatibility, since those are non-negotiable safety factors. Once you have a shortlist of medically cleared candidates, personal preferences come into play: physical characteristics, education level, hobbies, values, or the donor’s written responses about their motivation. Some people prioritize finding a donor who physically resembles them or their partner. Others care more about health history or personality.
If you’re working with a fertility clinic, ask whether they compare your carrier screening results against the donor’s before proceeding. Not all clinics do this automatically. Request the donor’s full medical and genetic profile rather than relying on a summary. For known donors, invest in both comprehensive genetic testing and a legal agreement before any medical procedures begin. The cost and effort upfront prevent far more painful complications later.