Superfecundation

Superfecundation is a rare occurrence in human reproduction where two or more ovum from the same menstrual cycle are fertilized by sperm from separate acts of sexual intercourse. The term is derived from the Latin words super meaning "over, above" and fecundare meaning "to fertilize".

Overview

Superfecundation most commonly happens within hours or days of the first instance of fertilization with ovum remaining viable for a period up to five days. The phenomenon is less likely to occur in humans due to the release of hormones after fertilization that typically prevents further ovulation.

Types

There are two types of superfecundation: heteropaternal superfecundation and homopaternal superfecundation. Heteropaternal superfecundation occurs when two different males father fraternal twins. Homopaternal superfecundation occurs when one male fathers two children in separate acts of intercourse that occur within the same menstrual cycle.

Occurrence in Humans

Superfecundation is more common in animals than in humans. In humans, the occurrence is rare and typically only comes to light through the use of genetic testing.

Occurrence in Animals

Superfecundation is common in animals such as cats and dogs. In these species, a litter of offspring can have different fathers.

Legal Implications

The legal implications of superfecundation can be complex, particularly in cases of heteropaternal superfecundation. Issues can arise in relation to child support and custody.

See Also

• Twin
• Multiple birth
• Fraternal twins
• Identical twins