D

DeoxyriboNucleicAcid (DNA): The major constituent of chromosomes, and the hereditary material of all living organisms. 

Dizygotic:  Derived from two (di) eggs (zygote). Dizygotic twins form when two separate eggs are fertilised by separate sperm.

Donor: Person who consents to allow their gametes or embryos to be used in the treatment of others or for research purposes. Although donors are the genetic parents of children created using their gametes, if the treatment is provided in a licensed centre in the UK they are not the legal parents of these children.

Donor Insemination (DI): The introduction of donor sperm into the vagina, the cervix or womb itself.