ASK A QUESTION what is your date of birth?
I would like to know how to ask a person what their date of birth is in a personal setting.
¿Qué es tu fecha de nacimiento? What is your date of birth? or ¿Cuándo naciste? When were you born?
How about "¿Cuál es la fecha de su (tu) nacimiento?"?
lo es su fecha de nacimiento
or you could say cuando naciste when were you born