There has been much said about the idea of sonship. The biblical language concerning sonship is almost exclusively ‘father’ and ‘son’. Concerning God and Christ, this must never be changed, but in the church there has to be some understanding. In this modern era women could feel excluded if they do not understand. Scripturally, all believers, men and women, boys and girls, are sons of God.
Furthermore, we are considered firstborn sons (Hebrews 12:23), since we are in Christ. If we were not counted as firstborn sons, we could not share a joint inheritance with Christ, it would instead be a partial inheritance. But we are joint-heirs, and each of us, with Him, inherits all the Father has.
Furthermore, St John refers to all believers as being either infants, children, young men, or fathers. It would become very ponderous, and you would soon tire of reading, if in every place that required personal pronouns the Bible recorded he/she, or him/her, and if, instead of simply saying ‘sons’. The scriptures often imply ‘sons and daughters’, or where required, ‘fathers and mothers’, where the words "sons" and "fathers" are written. Thus its important to be able to see yourself as included when the Bible may seem at times to use less inclusive language.
One interesting additional thought, is that all believers are often referred to as the wife of the lamb, or the Bride of Christ. Many men find this a hard concept to accept. So these figures of speech and ideas go both ways.
The conclusion we ought to draw is that God uses many pictures and illustrations from life to help us understand who He is, and what He is doing, and how we fit in. The great news is that we are included in His plans, regardless of whether we are male or female.