December 11. On this date in 1973, the Universal House of Justice wrote an individual "expressing concern that the provision of the Bahá'í marriage law requiring consent of living natural parents creates a double standard in your family because you have adopted children as well as your own" noting "the unity of your family need not be imperilled because your adopted children when ready for marriage must obtain consent of their natural parents."

December 11. On this date in 1973, the Universal House of Justice wrote an individual "expressing concern that the provision of the Bahá'í marriage law requiring consent of living natural parents creates a double standard in your family because you have adopted children as well as your own" noting "the unity of your family need not be imperilled because your adopted children when ready for marriage must obtain consent of their natural parents."

1251. Adopted Children and the Special Significance of Their Relationship with the Natural Parents
"We acknowledge receipt of your letter of November 13, 1973 expressing concern that the provision of the Bahá'í marriage law requiring consent of living natural parents creates a double standard in your family because you have adopted children as well as your own.
"We appreciate your concern and are in sympathy with your worthy aspiration to attain unity in your family group. However, the unity of your family need not be imperilled because your adopted children when ready for marriage must obtain consent of their natural parents. Just as love for one person need not reduce the love one bears to another, so unity with the adoptive parents need not destroy nor reduce the unity a child may have with its natural parents, or vice versa. The characters and attitudes of the individuals concerned will have an effect upon this.
"You also state that unless there is a broader concept of the meaning of 'natural parent', you feel the law creates disharmony. Perhaps the following extract from a letter written on behalf of the beloved Guardian by his secretary was quoted to you by your National Spiritual Assembly, but we draw your attention to that portion we have underlined because it refers to the special significance of the relationship between children and their natural parents.
'Bahá'u'lláh has clearly stated the consent of all living parents is required for a Bahá'í marriage.... This great law He has laid down to strengthen the social fabric, to knit closer the ties of the home, to place a certain gratitude and respect in the hearts of children for those who have given them life and sent their souls out on the eternal journey towards their Creator.'
"In short, love for the foster parents and unity with their home should not exclude love for a child's natural parents, although it is likely a child will become very much more a part of the home in which he lives and grows up.
"Of course, wherever the law of the land or the Agreement of Adoption prohibits future contact between an adopted child and its natural parents, the Bahá'í law does not require the child to seek the consent of those parents to its marriage. However, children may very well wish to obtain the consent of their foster parents although not obliged to do so."
(From a letter of the Universal House of Justice to an individual believer, December 11, 1973)