dibling dibling a dibling, a portmanteau of donor sibling, or donor-conceived sibling, or donor-sperm sibling, is one of two or more individuals who are biologically connected through donated eggs or sperm. the term is not favored among some donor-conceived people, who prefer the use of half-sibling. people born from anonymous or id release sperm or egg donation are able to find half-siblings conceived using the same gamete donor online through the donor sibling registry or by using commercially-available dna test kits. dna testing is more accurate because it relies on comparison of single-nucleotide polymorphisms instead of gamete donor identification numbers (which may be erroneous).