In Bible terminology, this can be either a direct male offspring or any subsequent descendant. Jesus is called ‘the son of David, the son of Abraham’ thus encompassing many generations (Mt 1:1). Believers are called “sons of God”, being adopted into the family of God (Deut 14:1; Rom 8:14,15; Gal 3:26). Each person (male and female) must enter into that personal relationship with God (through Jesus) on his or her own account, it being impossible to get into heaven through the decision of another.
See also: brother/sister.