Swiss voters will take part in Europe’s first election on same-sex unions on 5 June.
In other European countries, governments, not voters, have decided how to recognise same-sex relationships, 365Gay.com reported.
Swiss parliament last year passed laws to form a civil unions registry and give same-sex couples limited rights in areas such as pensions and tax.
However, conservatives have used a petition to force next month’s referendum.
Registered same-sex partnerships already exist in parts of Switzerland, 365Gay.com said.