One twin, the 'donor' twin, is small and anemic, the other, the 'recipient' twin, is large and polycythemic. The lives of both twins are endangered by this condition.

TWIN definition: either of two children or animals brought forth at a birth. See examples of twin used in a sentence.

Jan 2, 2026 · twin, either of two young who are simultaneously born from one mother. Twinning, common in many animals, is of two biological kinds: the one-egg (monozygotic), or identical, …

There are different types of twins, identical and fraternal being the most common. Identical, or monozygotic, twins develop from the same fertilized egg that splits into two. These twins are...

TWIN meaning: 1. either of two children born to the same mother on the same occasion: 2. one of two very similar…. Learn more.

1. Being two or one of two offspring born at the same birth: twin sisters. 2. Being two or one of two identical or similar people, animals, or things: twin cities; a twin bed. 3. Botany Of or relating to …

Dec 13, 2025 · Identical twins, also known as monozygotic twins, share the same egg at conception and are always either both boys or both girls. Fraternal twins, also known as …

Apr 25, 2023 · In a basic twin pregnancy, two embryos go their separate ways and develop into twin babies, whether identical or fraternal. Some unique sets of twins follow a different path.

If you have a twin brother or sister, the two of you are always the same age. There are identical twins, who have the same DNA, and fraternal twins, who are more like two siblings who …

either of two persons or things closely resembling each other. adj. [before a noun] being a twin or twins: twin sisters. being two persons or things closely related to each other. being one of a …