Shaykh Muhammad ibn Saalih al-‘Uthaymeen (may Allah have mercy on him) was asked:
“We often see in women’s gatherings girls and young girls, around the age of seven years, wearing short or tight clothes, or strange haircuts, or haircuts for small girls that look like haircuts for boys. If we speak to the mothers and try to advise them, they argue that the children are still small. We hope that you can give us clear advice about children’s clothing and haircuts, may Allah bless you.
It is well known that the individual is influenced by things in his childhood and will continue to be affected by them after he grows up. Hence the Prophet (blessings and peace of Allah be upon him) enjoined us to instruct our children to pray when they are seven years old, and to smack them (lightly) if they do not pray when they reach the age of ten, so that they will get used to it, as the child will follow that which he is used to. If a young girl gets used to wearing short clothes that only come to the knee, and short sleeves that only come to the elbow or shoulder, she will lose all modesty and will want to wear these clothes after she grows up. The same applies with regard to hair; a woman should have a hairstyle that is different from that of men; if she makes the hair like a man’s hair, she will be resembling men and the Prophet (blessings and peace of Allah be upon him) cursed women who resemble men.
It should be noted that the family is responsible for these children and their upbringing and education, as the Prophet (blessings and peace of Allah be upon him) said: “A man is the shepherd of his household and is responsible for his flock.” So beware of being heedless; the father should be serious about the upbringing of his sons and daughters, and he should care for them, so that Allah will guide them and they will become a delight to him.”
Al-Liqa’ al-Shahri, 66/10