Source : Webster's Revised Unabridged Dictionary (1913)

Nascency \Nas"cen*cy\, n. [L. nascentia. See {Nascent}.]
   State of being nascent; birth; beginning; origin.

Source : WordNet®

nascency
     n : the event of being born; "they celebrated the birth of their
         first child" [syn: {birth}, {nativity}, {nascence}] [ant:
          {death}]