How many letters does the top answer for “the properties characteristic of the female sex” have?

The most common answer is femaleness (10 letters).

Crossword clue: the properties characteristic of the female sex

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

femaleness 10 letters wn-def

the properties characteristic of the female sex

feminineness 12 letters wn-def

the properties characteristic of the female sex

the properties characteristic of the male sex 60% similar → maleness, masculinity