Narrated Aisha, Ummul Mu'minin:

The Prophet ﷺ was asked about a person who found moisture (on his body or clothes) but did not remember the sexual dream. He replied: He should take a bath. He was asked about a person who remembered that he had a sexual dream but did not find moisture. He replied: Bath is not necessary for him. Umm Salamah then asked: Is washing necessary for a woman if she sees that (in her dream)? He replied: Yes. Woman are counterpart of men.

حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا حَمَّادُ بْنُ خَالِدٍ الْخَيَّاطُ، حَدَّثَنَا عَبْدُ اللَّهِ الْعُمَرِيُّ، عَنْ عُبَيْدِ اللَّهِ، عَنِ الْقَاسِمِ، عَنْ عَائِشَةَ، قَالَتْ سُئِلَ رَسُولُ اللَّهِ ﷺ عَنِ الرَّجُلِ يَجِدُ الْبَلَلَ وَلاَ يَذْكُرُ احْتِلاَمًا قَالَ " يَغْتَسِلُ " . وَعَنِ الرَّجُلِ يَرَى أَنَّهُ قَدِ احْتَلَمَ وَلاَ يَجِدُ الْبَلَلَ قَالَ " لاَ غُسْلَ عَلَيْهِ " . فَقَالَتْ أُمُّ سُلَيْمٍ الْمَرْأَةُ تَرَى ذَلِكَ أَعَلَيْهَا غُسْلٌ قَالَ " نَعَمْ إِنَّمَا النِّسَاءُ شَقَائِقُ الرِّجَالِ " .