twin

Also known as twin person

thumb|Identical twins can be difficult to visually distinguish especially when young, as demonstrated by brothers Billy and Bobby Mauch. Twins are two offspring produced by the same pregnancy. Twins can be either monozygotic ('identical'), meaning that they develop from one zygote, which splits and forms two embryos, or dizygotic ('non-identical' or 'fraternal'), meaning that each twin develops from a separate egg and each egg is fertilized by its own sperm cell. Since identical twins develop from one zygote, they will share the same sex, while fraternal twins may or may not. In very rare cas

AI overview

Twins are two offspring born from the same pregnancy, and they can be either identical (developing from a single egg that splits into two embryos) or fraternal (developing from two separate eggs each fertilized by different sperm). Identical twins share the same sex and genetics, while fraternal twins may be different sexes and share only about half their DNA, similar to regular siblings.

AI-generated from the Wikipedia summary — may contain errors.

Research

91,693 papers

Update on Management and Outcomes of Monochorionic Twin Pregnancies.ReviewObstetrics and gynecology · 2025Simpson LLDOI: 10.1097/AOG.0000000000005891
Heritability of Schizophrenia and Schizophrenia Spectrum Based on the Nationwide Danish Twin Register.Biological psychiatry · 2018Hilker R, Helenius D, Fagerlund B et al.DOI: 10.1016/j.biopsych.2017.08.017
Twin Family Registries Worldwide: An Important Resource for Scientific Research.Twin research and human genetics : the official journal of the International Society for Twin Studies · 2019Hur YM, Bogl LH, Ordoñana JR et al.DOI: 10.1017/thg.2019.121
US Evaluation of Twin Pregnancies: Importance of Chorionicity and Amnionicity.ReviewRadiographics : a review publication of the Radiological Society of North America, Inc · 2019Jha P, Morgan TA, Kennedy ADOI: 10.1148/rg.2019190042
Polygenic Risk Scores and Twin Concordance for Schizophrenia and Bipolar Disorder.JAMA psychiatry · 2024Song J, Pasman JA, Johansson V et al.DOI: 10.1001/jamapsychiatry.2024.2406
Managing Monoamniotic Twin Pregnancies.Clinical obstetrics and gynecology · 2023Post ALDOI: 10.1097/GRF.0000000000000817
Managing Monoamniotic Twin Pregnancies.ReviewClinical obstetrics and gynecology · 2015Post A, Heyborne KDOI: 10.1097/GRF.0000000000000118
Twin children's language development.ReviewEarly human development · 2006Thorpe KDOI: 10.1016/j.earlhumdev.2006.03.012

via PubMed

Wikidata facts

Image: Faucher, frères.jpg

Show 4 more facts

Commons gallery: Twin
female form of label: Zwillingsschwëster
male form of label: Zwillingsbrudder
kinship equivalent in SPARQL at Wikidata: ?person wdt:P3373 ?relative ; wdt:P569 ?dob . ?relative wdt:P569 ?dob

Sources (2)

via Wikidata · CC0

~42 min read

Article

38 sections

Contents

<span lang="Indoneaia" dir="ltr">Statistics</span>
Types and zygosity
{{anchor|Fraternal|Fraternal twins|Dizygotic|Fraternal (dizygotic) twins}}Dizygotic (fraternal) twins
{{Anchor|IdenticalTwins|Identical twins|Identical (monozygotic) twins}}Monozygotic (identical) twins
Mechanism
Incidence
Genetic and epigenetic similarity
Polar body and semi-identical twins
Degree of separation
Demographics
Ethnicity
Predisposing factors
Delivery interval
Complications during pregnancy
Vanishing twins
Conjoined twins
Chimerism
Parasitic twins
Partial molar twins
Miscarried twin
Low birth weight
Twin-to-twin transfusion syndrome
Stillbirths
Heterotopic pregnancy
Management of birth
Human twin studies
Unusual twinnings
Bi-paternal twins
Mixed twins
Monozygotic twins of different sexes
{{anchor|Dizygotic (fraternal) twins|Half-identical twins}}Semi-identical (sesquizygotic) twins
Mirror image twins
Language development
Animals
See also
References
Further reading
External links

In contrast, a fetus that develops alone in the womb (the much more common case in humans) is a singleton; one of a multiple birth is a multiple. Unrelated look-alikes whose resemblance parallels that of twins are referred to as doppelgänger.