Both the one who makes people holy and those who are made holy are of the same family. So Jesus is not ashamed to call them brothers and sisters. Hebrews 2:11 (NIV)
My wife is an only child, so she never had brothers and sisters as she was growing up. She has often spoken of the wish she had to have either a brother or sister. However, when she became a Christian she suddenly acquired a new family that had plenty of brothers and sisters.
Are you an only child? If so, take encouragement from the fact that as part of God’s family you are no longer alone. God’s family transcends national and international boundaries, cultures and skin colour. Enjoy the diversity of your new family.