How many letters does the top answer for “the event of being born” have?

The most common answer is nascence (8 letters).

Crossword clue: the event of being born

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

nascence 8 letters wn-def

the event of being born

nascency 8 letters wn-def

the event of being born

being born or beginning 50% similar → nascent