Determining the single "rarest" baby born is impossible without a globally comprehensive database of births and their unique characteristics. However, we can examine rarity in different contexts.
Rarest Birthday
The rarest birthday is February 29th, also known as Leap Day. This is because it only occurs every four years during a leap year. The chance of being born on this date is approximately 1 in 1,461. [Source: Happiest Baby, Greenlight]
Rarest Birth Conditions
Medical rarity offers another perspective. Numerous extremely rare birth defects and genetic conditions make certain babies exceptionally unusual. For example, congenital arhinia, where a baby is born without a nose, is incredibly uncommon, with only about 50 documented cases globally. [Source: Global Genes] Many other conditions with similarly low occurrence rates exist.
Rarest Animal Births
Even outside of human births, rarity applies. For instance, the birth of a critically endangered baby addax antelope at Disney is considered exceptionally rare due to the species' low population numbers. [Source: Disney Parks Blog]
The question needs clarification. "Rarest" requires a specific definition. Is it rarest birthday, rarest genetic condition, or rarest species? Without a defined metric, a single definitive answer isn't possible.
