A woman asked the Prophet ﷺ, "Does a woman need to bathe if she has a wet dream and sees the fluid?"He replied, "Yes."Ayesha said to her, "May your hands be covered in dust!"The Prophet ﷺ said, "Leave her alone. How else does the resemblance come about? If her fluid prevails over the man's fluid, the child resembles his maternal uncles, and if the man's fluid prevails over hers, the child resembles him."
حدثنا قتيبة حدثنا يحيى بن زكريا عن أبيه عن مصعب بن شيبة عن مسافع بن عبد الله الحجبي عن عروة بن الزبير
أن امرأة قالت للنبي ﷺ هل تغتسل المرأة إذا احتلمت وأبصرت الماء فقال نعم فقالت لها عائشة تربت يداك فقال النبي ﷺ دعيها وهل يكون الشبه إلا من قبل ذلك إذا علا ماؤها ماء الرجل أشبه أخواله وإذا علا ماء الرجل ماءها أشبهه
Its isnad is sahih. Musafi bin Abdullah al-Hajabi is trustworthy, and his hadith is found in Muslim. The hadith was narrated by Bukhari 1/388, no. 282, in the Book of Knowledge, and by Muslim 1/250, no. 314, in the Book of Menstruation. It has been mentioned many times before.