A WOMAN WHO PRAYS BEHIND A MAN IS NOT INFERIOR.
This form of prayer is sacred because the Prophet, pbuh, taught it.
Umm Sulaim, r.a. Mother of Anas ibn Malik prayed behind her son. Only an ignorant person would claim that she was inferior to the boy she brought up and taught.
The form of prayer, the formal separation between men and women, has nothing to do with inferiority and superiority. It has to do with MODESTY, which, we learn from Hadith, is an essential part of Faith in Islam.
Prophet Muhammad pbuh reminded us that Modesty and Faith are integral to each other, when one goes the other goes too.
Men and women are equal in reward as Allah says in the Quran:
وَمَن يَعْمَلْ مِنَ الصَّالِحَاتِ مِن ذَكَرٍ أَوْ أُنثَىٰ وَهُوَ مُؤْمِنٌ فَأُولَـٰئِكَ يَدْخُلُونَ الْجَنَّةَ وَلَا يُظْلَمُونَ نَقِيرًا ﴿١٢٤﴾
[4:124] Yusuf Ali
If any do deeds of righteousness,- be they male or female – and have faith, they will enter Heaven, and not the least injustice will be done to them.
مَنْ عَمِلَ صَالِحًا مِّن ذَكَرٍ أَوْ أُنثَىٰ وَهُوَ مُؤْمِنٌ فَلَنُحْيِيَنَّهُ حَيَاةً طَيِّبَةً ۖ وَلَنَجْزِيَنَّهُمْ أَجْرَهُم بِأَحْسَنِ مَا كَانُوا يَعْمَلُونَ ﴿٩٧﴾
Allah Subhanawataala says in Surat an-Nahl (the Bee): 97
[16:97] Yusuf Ali
Whoever works righteousness, man or woman, and has Faith, verily, to him will We give a new Life, a life that is good and pure and We will bestow on such their reward according to the best of their actions.
وَلَا تَتَمَنَّوْا مَا فَضَّلَ اللَّـهُ بِهِ بَعْضَكُمْ عَلَىٰ بَعْضٍ ۚ لِّلرِّجَالِ نَصِيبٌ مِّمَّا اكْتَسَبُوا ۖ وَلِلنِّسَاءِ نَصِيبٌ مِّمَّا اكْتَسَبْنَ ۚ وَاسْأَلُوا اللَّـهَ مِن فَضْلِهِ ۗ إِنَّ اللَّـهَ كَانَ بِكُلِّ شَيْءٍ عَلِيمًا ﴿٣٢﴾
[4:32] Yusuf Ali
And in no wise covet those things in which Allah Hath bestowed His gifts More freely on some of you than on others: To men is allotted what they earn, and to women what they earn: But ask Allah of His bounty. For Allah hath full knowledge of all things.
Thus He subhanawataala is the judge of who is best in actions irrespective of gender.