Is it permissible for a father to forbid his son and daughter from touching each other, out of concern that it may be a cause of fitnah

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

The father is responsible for his children who are a trust with him, and he must do everything to protect them and safeguard their religion; Allaah says (what means): {O you who have believed, protect yourselves and your families from a Fire whose fuel is people and stones, over which are [appointed] angels, harsh and severe; they do not disobey Allaah in what He commands them but do what they are commanded.} [Quran 66:6]

Ibn ‘Abbaas said while interpreting this verse: “It means, teach them and discipline them.”

Also, Ibn ‘Umar said: “I heard the Prophet, sallallaahu ‘alayhi wa sallam, saying: ‘Every one of you is a guardian and is responsible for the people under his guardianship… and a man is a guardian in his house and is responsible for the people under his guardianship.’” [Al-Bukhari and Muslim]

It is in this context that the guidance of the Prophet, sallallaahu ‘alayhi wa sallam, came, as in the Hadeeth regarding separating between the children in beds. Commenting on this Hadeeth, Al-Munaawi said in Faydh al-Qadeer: “It means separating between the children in their beds on which they sleep when they reach ten years of age as a precaution against the dangers of lust even if they are his sisters.” [End of quote]

For more benefit, please refer to Fatwa 249073.

Therefore, if the father is suspicious about the brother touching his sister or vice-versa, then he is obliged to prevent what he fears to lead to temptation as a way of preventing what leads to evil and what is forbidden from taking place.

However, it should be noted here that it is very serious for the father to resort to preventing them just because of obsessive whispers and illusions, as by this the devil may incite in the heart of the children to do evil and reinforces it for them, and introduces it after it did not exist. If is for this reason that the scholars praised jealousy when there is suspicion and dispraised it when there is no suspicion.

Allaah Knows best.