Superfecundation is the fertilization of two or more
, abbreviated as OVA and sometimes as OAV (original animation video), are Japanese animated films and series made specially for release in home video formats without prior showings on television or in theaters, though the first part of an OVA ...
from the same cycle
Sperm is the male
Male ( symbol: ♂) is the sex of an organism that produces the gamete (sex cell) known as sperm, which fuses with the larger female gamete, or ovum
The egg cell, or ovum (plural ova), is the female reproductiv ...
from separate acts of
Sexual intercourse (or coitus or copulation) is a sexual activity
Human sexual activity, human sexual practice or human sexual behaviour is the manner in which human
Humans (''Homo sapiens'') are the most abundant and widesprea ...
, which can lead to twin babies from two separate biological fathers. The term superfecundation is derived from
Fecundity is defined in two ways; in human demography, it is the potential for reproduction of a recorded population
Population typically refers to the number of people in a single area, whether it be a city or town
A town is a h ...
, meaning the ability to produce offspring. Homopaternal superfecundation is fertilization of two separate ova from the same father, leading to
Twins are two offspring
Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms a ...
while heteropaternal superfecundation is a form of atypical twinning where, genetically, the twins are half siblings – sharing the same mother, but with different fathers.
Sperm cells can live inside a female's body for up to five days, and once ovulation occurs, the egg remains viable for 12–48 hours before it begins to disintegrate. Superfecundation most commonly happens within hours or days of the first instance of fertilization with ova released during the same cycle.
Ovulation is the release of eggs from the ovaries. In women
A woman is an adult female human
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cogni ...
is normally suspended during
Pregnancy is the time during which one or more offspring
Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent f ...
to prevent further ova becoming fertilized and to help increase the chances of a full-term pregnancy. However, if an ovum is atypically released after the female was already impregnated when previously ovulating, a chance of a second pregnancy occurs, albeit at a different stage of development. This is known as
Superfetation (also spelled superfoetation – see fetus
A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo
An embryo is an initial stage of development of a multi ...
Heteropaternal superfecundation is common in animals such as cats and dogs. Stray dogs can produce litters in which every puppy has a different sire. Though rare in humans, cases have been documented. In one study on humans, the frequency was 2.4% among dizygotic twin
s whose parents had been involved in paternity suit
Cases in Greek mythology
A major branch of classical mythology, Greek mythology is the body of myths originally told by the ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the origin and nature of the world, the lives and activities ...
holds many cases of superfecundation:
lies with both her husband
In Greek mythology
A major branch of classical mythology, Greek mythology is the body of myths originally told by the ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the origin and nature of the world, the ...
and with the god
Zeus or , , ; grc, Δῐός, ''Diós'', label= genitive Boeotian Aeolic and Laconian grc-dor, Δεύς, Deús ; grc, Δέος, ''Déos'', label= genitive el, Δίας, ''Días'' () is the sky and thunder god in ancient Greek reli ...
, the latter in the guise of a swan. Nine months later, she bears two daughters: Clytemnestra
by Tyndareus and Helen
by Zeus. This happens again; this time Leda bears two sons: Castor by Tyndareus and Pollux by Zeus
lies with Zeus, who is disguised as her husband
Amphitryon (; Ancient Greek
Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world
Ancient history is a time period from the beginning of writing and recorded human history to ...
; Alcmene later lies with the real Amphitryon and gives birth to two sons: Iphicles
by Amphitryon and
Heracles ( ; grc-gre, Ἡρακλῆς, , glory/fame of Hera), born Alcaeus (, ''Alkaios'') or Alcides (, ''Alkeidēs''), was a divine hero in Greek mythology
A major branch of classical mythology, Greek mythology is the body of ...
lies with both
Apollo, grc, Ἀπόλλωνος, Apóllōnos, label=genitive , ; , grc-dor, Ἀπέλλων, Apéllōn, ; grc, Ἀπείλων, Apeílōn, label= Arcadocypriot Greek, ; grc-aeo, Ἄπλουν, Áploun, la, Apollō, la, Apollinis, label ...
Hermes (; grc-gre, Ἑρμῆς) is an Olympian deity
A deity or god is a supernatural being who is considered divine or sacred. The ''Oxford Dictionary of English'' defines deity as a god or goddess, or anything revered as divi ...
on the same night, and falls pregnant. She bears two sons;
In Greek mythology
A major branch of classical mythology, Greek mythology is the body of myths originally told by the ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the origin and nature of the world, th ...
for Hermes and Philammon
Selected cases involving superfecundation
In 1982, twins who were born with two different skin colors were discovered to be conceived as a result of heteropaternal superfecundation.
In 1995, a young woman gave birth to diamniotic monochorionic twins, who were originally assumed to be monozygotic twins until a paternity suit led to a DNA test. This led to the discovery that the twins had different fathers.] [
In 2001, a case of spontaneous monopaternal superfecundation was reported after a woman undergoing IVF treatments gave birth to quintuplets after only two embryos were implanted. Genetic testing supported that the twinning was not a result of the embryos splitting, and that all five boys shared the same father.] [
In 2015, a judge in ] New Jersey
New Jersey is a state in the Mid-Atlantic and Northeastern regions of the United States. It is bordered on the north and east by the state of New York; on the east, southeast, and south by the Atlantic Ocean
The Atlantic Ocean is ... ruled that a man should only pay child support for one of two twins, as the mother had sex with two different men within a week.
In 2016, an IVF-implanted surrogate mother gave birth to two children: one genetically unrelated child from an implanted embryo, and a biological child from her own egg and her husband's sperm.
In 2019, a Chinese woman was reported to have two babies from different fathers, one of whom was her husband and the other was a man having a secret affair with her during the same time.
In 2022, a 19-year-old Brazilian from Mineiros gave birth to a twin from two different fathers with whom she had sex on the same day.
* Chimera (genetics)
* Mixed twins
* Polyandry in nature