Donor conceived person
A donor offspring, or donor conceived person, is conceived via the donation of sperm (sperm donation) or ova (egg donation), or both, either from two separate donors or from a couple. In the case of embryo donation, the conceiving parents are a couple.
Donor conceived people may never learn of their true birth origins as information about their true genetic parent(s) is not recorded on the birth certificate. Donor conceived people may have many half siblings as a result of the same person's donations.
With the significant increase in the numbers of donor-conceived individuals (38,910 live babies were born in 2005 as a result of 134,260 ART cycles performed at reporting U.S. clinics in 2005, compared with 20,659 babies born as a result of 64,036 ART cycles in 1996), many have questioned the ethics surrounding the technologies and human decisions surrounding donor conception, and there has been plenty of controversy. For example, the term "Snowflake baby" was coined in reference to unused frozen embryos (left over from other couples' attempts to conceive through in vitro fertilization) that have been "adopted" by families. Pro-life advocates tend to support such adoptions.
The psychological and social impacts of assisted reproductive technologies (ART) on donor-conceived children and their families has gained a great deal of interest in recent years as this population has continued to grow. An increasing number of family-support organizations strongly encourage parents to openly discuss their children's origins, whether through donor insemination or following treatment with donated gametes. Studies[which?] suggest that the parents' level of comfort with their use of donor conception positively influences the mental health of their donor-conceived offspring.
For most sperm or egg recipients, the choice between anonymous sperm or egg donor and a non-anonymous one is generally not of major importance. For some donor conceived children, on the other hand, it may be psychologically burdensome not having the possibility of contacting or knowing almost nothing about the biological father. Thus far, studies have found that a significant number of donor conceived children want information about their biological father.
Coming forward publicly with problems is difficult for donor-conceived people as these issues are very personal and a public statement may attract criticism but ultimately are the only remaining option in activism on the issue. Additionally, it may upset their parents if they speak out. A website called Anonymous Us  has been set up where they can post details of their experiences anonymously, on which there are many accounts of problems.
Donor and sibling tracking
There are donor sibling registries matching genetic siblings and donors. However, with modern information technology, there are other ways of getting information.
A donor registrations facilitate donor conceived people, sperm donors and egg donors to establish contact with genetic kindreds. They are mostly used by donor conceived people to find genetic half-siblings from the same egg- or sperm donor.
Some donors are non-anonymous, but most are anonymous, i.e. the donor conceived person doesn't know the true identity of the donor. Still, he/she may get the donor number from the fertility clinic. If that donor had donated before, then other donor conceived people with the same donor number are thus genetic half-siblings. In short, donor registries matches people who type in the same donor number.
Alternatively, if the donor number isn't available, then known donor characteristics, e.g. hair, eye and skin color may be used in matching siblings.
Clinics or sperm banks
Many clinics and sperm banks offer non-anonymous donors, such as where the donor conceived person may get the identity of the donor.
However, an Australian study came to the result that potential donors who would still be willing to donate without a guarantee of anonymity were not automatically more open to initiate or extended contact with offspring. Most potential donors would be willing to meet offspring in a single contact.
However, even sperm donors who have not initiated contact through a registry are now increasingly being traced by their offspring. In the current era there can be no such thing as guaranteed anonymity. Through the advent of DNA testing and internet access to extensive databases of information, one sperm donor has recently been traced. Current reliable DNA testing can be done through 23andMe  and Family Tree DNA  In 2005 it was revealed in New Scientist magazine that an enterprising 15-year-old used information from a DNA test and the internet to identify and contact his genetic father, who was a sperm donor. This has brought into question the ability of sperm donors to stay anonymous.
- Wanted: A Few Good Sperm nytimes.com Published: March 19, 2006
- Ekerhovd E, Faurskov A, Werner C (2008). "Swedish sperm donors have been said to be driven by altruism, but shortage of sperm donors leads to reproductive travelling". Ups. J. Med. Sci. 113 (3): 305–13. doi:10.3109/2000-1967-241. PMID 18991243.
- Donor Babies Search for Their Anonymous Fathers. By Craig Malisow. Published on November 04, 2008 at 11:22am
- Telegraph.co.uk: Sperm donors should get cut-price IVF to tackle shortage By Rebecca Smith, Medical Editor in San Francisco. Last Updated: 4:12PM GMT 11 November 2008. This ref, in turn, cites Dr Joanna Sheib from the University of California Davis
- Ilioi, E. C.; Golombok, S. (2014). "Psychological adjustment in adolescents conceived by assisted reproduction techniques: a systematic review". Human Reproduction Update 21 (1): 84–96. doi:10.1093/humupd/dmu051. ISSN 1355-4786.
- Van Den Broeck, U.; Vandermeeren, M.; Vanderschueren, D.; Enzlin, P.; Demyttenaere, K.; d'Hooghe, T. (2012). "A systematic review of sperm donors: Demographic characteristics, attitudes, motives and experiences of the process of sperm donation". Human Reproduction Update 19 (1): 37–51. doi:10.1093/humupd/dms039. PMID 23146866.
-  New Scientist article about a 15-year-old who found his donor using a DNA test]
- Information for donor conceived people - UK Regulator (Human Fertilisation and Embryology Authority)