Absence of hymen is not a reliable indicator of virginity. Justify.

This statement is absolutely correct. Hymen is just a thin skin covering which protect the vagina. It's not necessary that hymen would break only during coitus, in some females hymen would be broken before the intercourse due to various possible reasons like- if a women is a sport person or has an active lifestyle, there are possibilities of breakage of hymen. Thus, we cannot judge the virginity of any women on the presence of hymen.

@Shreya:- Good answer, keep contributing!!