About the consent of parents for marriage: this is required before and also after the man or woman is twenty-one years of age. It is also required in the event of a second marriage, after the dissolution of the first whether through death or through divorce.
The parental consent is also a binding obligation irrespective of whether the parents are Bahá'ís or not, whether they are friendly or opposed to the Cause. In the event of the death of both parents, the consent of a guardian is not required. (From a letter dated 10 October 1936 written on behalf of Shoghi Effendi to an individual believer; compilation ‘Consent of Parents to Marriage’, prepared by the Research Department of the Universal House of Justice)