) refers to the process of a diploid ovum
becoming fertilized by a monoploid sperm
. The result of digyny is a triploid zygote
. In humans, both gametes
(ovum and sperm) are normally monoploid and give rise to a diploid zygote.
Digyny results in gestational abnormalities in humans, including an abnormally small placenta and a very growth-restricted fetus. As a result, the majority of triploid pregnancies are spontaneously aborted. The incidence rate of a live-born triploid human is approximately 1 in 50,000.
- Stedman's Medical Dictionary, 27th edition, page 501.