I say, and with God's help: It is not obligatory for a father to pay Zakat al-Fitr for his adult, sane children, whether they are male or female, even if they are dependent on him as they are poor; because the reason for the obligation to pay Zakat al-Fitr for others is that there is a person who is dependent on him and over whom he has complete guardianship. Although he is obligated to provide for them, he does not have complete guardianship over them, thus one part of the reason is absent, and it is not obligatory. The hadith of the Prophet (peace be upon him): ‘Pay for every free person and servant, young or old, whom you support’ is understood as allowing payment for them, not as an obligation. See: Rad al-Muhtar 2: 75, Bada'i al-Sana'i 2: 70-71, Al-Wiqayah p. 230, and God knows best.