fraternal twin
Noun: A fraternal twin is one of a pair of twins who develop from two separate eggs (ova) fertilized by two separate sperm cells. They are genetically similar to ordinary siblings, sharing approximately 50% of their genes, and can be of the same or different sexes.
The term is used specifically in biology, medicine, and general conversation to describe a type of twinning, distinguishing it from identical (monozygotic) twinning. - It functions as a countable noun. - It is often used in the plural form "fraternal twins" to refer to the pair.
- As a subject:
- As an object:
- In the plural form:
- Scientific/Medical Context: The formal biological term for fraternal twins is dizygotic twins (originating from two zygotes). This term is often used interchangeably with "fraternal twins" in technical writing.
- The study compared cognitive development in monozygotic and dizygotic twins.
- Dizygotic twin (n): The technical, scientific synonym for a fraternal twin.
- Non-identical twin (n): A common alternative term, especially in British English.
- Fraternal (adj): Of or relating to brothers; brotherly. In the context of twins, it specifically denotes this type of twinning.
- They have a very fraternal bond.
- Dizygotic twin
- Non-identical twin
- Biovular twin (less common)
- Identical twin (a twin developed from a single fertilized egg that splits)
- Monozygotic twin (the technical term for an identical twin)
The key distinction lies in the biological origin. Unlike identical twins, fraternal twins: 1. Have separate placentas and amniotic sacs during pregnancy. 2. Are no more genetically alike than any pair of siblings born at different times. 3. Can be male/male, female/female, or male/female pairs.
The term "fraternal" itself means "brotherly," but it is used for this type of twinning regardless of the twins' sexes.
- either of two twins who developed from two separate fertilized eggs