There's a common policy that bone marrow patient and donor aren't allowed to meet or reveal their identities. In some countries they can't meet for a year of two after the transplant. In some others - for life.
I've search FAQ's of multiple bone marrow database foundations and I can't find an answer - why? Why are patient and donor prohibited from meeting or disclosing their identities for so long?
It's not that they can't meet. Meetings can and do happen and there's no medical reason they can't. In fact, most organ procurement programs have a system in place for allowing donors and recipients to meet.
Does a donor family learn who receives the organs?
The identity of both the donor and the recipient are kept anonymous. If the donor family and/or the recipient wish to do so, they can exchange letters through UW Organ and Tissue Donation. After an exchange of letters, a signed release of information is required by both parties prior to UWHC releasing any information to the parties. At that point, if both parties would like, a meeting can be arranged at a future date. Either or both parties have the right to remain anonymous and the privacy of both parties is protected by Federal law.
It's long been standard practice to withhold donors' and recipients' identities from each other for privacy reasons. As the above notes, telling either of them the other's identity would violate medical privacy laws in most countries since that information tells them something (perhaps a lot) about that other party's medical history. If identities are made known, it would definitely require written permission from both parties.
But even without privacy laws, there's little or nothing to be gained by either party knowing the other's identity, and potentially a lot of conflict. For example, a family that has lost a loved one might very well not wish to be reminded of that by a recipient contacting them. And vice versa -- recipients might not want the discomfort of meeting the parents of the dead 16-year old whose organs are now theirs. It could be embarrassing, uncomfortable, and emotionally disturbing. There's also the risk of mental/emotional instability from either party. Can you imagine the nightmare of grieving parents feeling they just had to have a close personal relationship with you because you're walking around with their daughter's liver?
Granted, marrow donors aren't usually deaths, but all the same principles still apply. In short, this is an ethics question, not a health question. There is no medical reason marrow donors and recipients can't or shouldn't meet.
In the end, I decided to just ask bone marrow registry foundation, well, one of them, this exact question.
The response I got was that if it was allowed for the donor and the patient to meet in person, a strong emotional bond could be established between the two. In case another bone marrow transplant would be needed later, the decision to donate again, or not to, that donor would need to make, would be influenced by the personal relationship with the patient, and that's something this "no meet" rule is trying to prevent/limit.
The length of a common 2 year period during which patient and donor cannot meet isn't arbitrary either - it takes around 2 years from the date of the transplant to be able to confirm, with a high enough certainty, that patient is going to be healthy in the long term, which means donor will not be (probably) asked for another donation.
That's the explanation I got from that particular person in that particular clinic. I wouldn't be surprised if that "no meet" rule was established for more than one reason, and the ones @Carey Gregory listed in his answer make sense too, obviously.
