"Prohibited to you (For marriage) are:- Your mothers, daughters, sisters; father's sisters, Mother's sisters; brother's daughters, sister's daughters; foster-mothers (Who gave you suck), foster-sisters; your wives' mothers; your step-daughters under your guardianship, born of your wives to whom ye have gone in,- no prohibition if ye have not gone in;- (Those who have been) wives of your sons proceeding from your loins; and two sisters in wedlock at one and the same time, except for what is past; for Allah is Oft-forgiving, Most Merciful;" - Quran 4:23 (read more)

"....The women asked, "O Allah's Apostle! What is deficient in our intelligence and religion?" He said, "Is not the evidence of two women equal to the witness of one man?" They replied in the affirmative. He said, "This is the deficiency in her intelligence. Isn't it true that a woman can neither pray nor fast during her menses?" The women replied in the affirmative. He said, "This is the deficiency in her religion." - Sahih Bukhari 1:6:301 (read more)

"Aisha was still a child when Muhammad married her, and she continued to play with her toys." - William Montgomery Watt