The Policy Council has proposed the change to the adoption law while highlighting other deficiencies that will be reviewed.
Adoption was legalised in Guernsey on 22 March 1939, but there was no law until 1960.
Under the 1960 legislation, unmarried and same sex couples are unable to adopt together.
Couples are currently able to be assessed and approved as permanent carers for a child, but only one of the couple will be able formally to adopt the child.
'The introduction of the Children (Guernsey and Alderney) Law, 2008, provided the other carer with the option to obtain parental responsibility for the adopted child through an application to the court for a parental responsibility order,' said the Policy Council report.
'Although this allows both carers to have parental responsibility, this does not put them on an equal footing, as one carer will, by law, be given a lesser status in relation to the adopted child.
'The adoption law currently means that only one of them will be treated as the parent, while the other carer does not appear on the child's new birth certificate, and can be at risk of losing the parental responsibility granted.
'This restriction on unmarried and same sex couples does not fit with modern society, where a significant number of couples in settled and enduring relationships are not married, or recognised as married by the adoption law.'