Twins?

Riddle: Two girls were born to the same mother, on the same day, at the same time, in the same month and year and yet they're not twins. How can this be?

Answer: The two babies are two of a set of triplets.

Source: https://www.riddles.com/2793

Two girls were born to the same mother, on the same day, at the same time, in the same month and year and yet they're not twins. How can this be? — Twins? by 6085 v1.

Riddle: Two girls were born to the same mother, on the same day, at the same time, in the same month and year and yet they're not twins. How can this be? Answer: The two babies are two of a set of triplets. — by 6085 v2.