A consultation is being held on opening up civil partnerships to heterosexual couples in Scotland.
The Scottish government is seeking public views on the issue following a landmark ruling in June.
The UK Supreme Court said then that the law as it stands in the UK goes against the European Convention on Human Rights (ECHR) on equality grounds.
The secular partnerships became available to same-sex couples in 2005 following a change in legislation.
The consultation puts forwards two options - barring further partnerships or opening up civil partnerships to opposite-sex couples.
Social Security and Older People Secretary Shirley-Anne Somerville said: "This is very simply about ensuring equality.
"The Supreme Court made it clear that the Civil Partnership Act 2004 is not compatible with the European Convention on Human Rights because civil partnership is open to same-sex couples only, whereas marriage is open to everyone.
"That judgment related to England and Wales but the facts and circumstances in Scotland are very similar.
"Therefore, we must now consult on the future of civil partnership in Scotland and I would urge anyone with an interest in this area to take part."
Call to back extension
Equalities campaigners Rebecca Steinfeld and Charles Keidan won their Supreme Court challenge in June when justices ruled the Civil Partnership Act's restriction to same sex couples is discriminatory.
Scottish Green equalities spokesman Patrick Harvie called for people to back an extension of civil partnerships.
He said: "The Supreme Court ruling was very welcome, challenging the lack of choice available to mixed-sex couples.
"The way to correct this is not to roll back the clock and restrict that choice for everyone, but to allow all couples to choose what's right for them: marriage, civil partnership or cohabitation.
"Anything else would be a return to the bad old days, when the government decided what the best family structure was and simply imposed it on people."
'Freedom to choose'
Gordon MacRae, chief executive of Humanist Society Scotland, welcome the consultation.
He said: "We believe all couples should have the freedom to choose marriage or civil partnership and the current system must now be opened up.
"We know that there is demand from opposite-sex couples who have approached Humanist Society Scotland looking for a civil partnership rather than a marriage and we believe they should be given that choice.
"If civil partnerships are extended, there should also be consideration given to removing gender entirely from the marriage laws - given that marriage and civil partnership will be equally available to both same-sex and opposite-sex couples."
Scottish Liberal Democrat MSP Alex Cole-Hamilton said: "It seems only sensible to allow mixed-sex couples to choose the form of partnership best suited to them.
"Now it's up to the government to get on with the legislation and ensure that there are no hurdles in the way of equality."
The Scottish government consultation closes on 21 December and the government has pledged to then take a decision to ensure future compatibility with the ECHR.