Two offspring that develop from two zygotes but share a common uterine environment, and would be born at the same birth
Twins refer to the two offspring that are brought forth by the same pregnancy and birth. Twins may be monozygotic (or identical) or dizygotic (fraternal).
Dizygotic twins are twins that develop from two zygotes. Dizygotic twins are non-identical because they arise from two eggs, each fertilized by a sperm. They are siblings who have shared a common uterine environment. They are due to fertilization of two different ova by different sperm. Dizygotic twins are also called fraternal twins.
Spontaneous dizygotic twinning occurs when two ova are released from the ovary simultaneously and are fertilized by two sperm cells. As a result, two fertilized ova would be implanted in the uterine wall and would have separate placenta and membranes. They may be of the same sex or of opposite sex. Since the twins developed from separate zygotes the siblings would differ genetically. They may also look very different from each other.
Word origin: Greek dís (“twice”) + zygotic (zygote) twins
Abbreviation / Acronym: DZ twins
- fraternal twins
- diovular twins
- dichorial twins
- heterologous twins
- binovular twins
- dissimilar twins
- non-identical twins
- false twins