Dawn Allen is the unborn child of Barry Allen and Iris West-Allen. Her twin brother Don is the father of Impulse.
Iris found out she was pregnant in the morning, but decided to hold off telling her husband until the evening, when they'd have privacy, after celebrating the Garricks' wedding anniversary.
The sudden arrival of Impulse spoiled the surprise. However, Iris was shocked to learn she was pregnant with not one child, but two, a boy and a girl he referred to as Aunt Dawn.
- In the comics, Don and Dawn Allen, also known as the Tornado Twins, are the children of Barry Allen and Iris West-Allen. Dawn Allen was the mother of Legion of Super-Heroes member XS (Jenni Ognats).