The department has told British nationals and their EU partners that children born abroad to a British parent (who was also born outside of the country) are ineligible for citizenship.
Some EU countries do not recognise same-sex partnerships and denied children citizenship on that basis.
This leaves them stateless as neither country has issued documentation.
Many same-sex parents have been left in an uncertain position and have not been able to leave the country where their child was born because they can’t get a passport or other identity documents for them.
One family’s three-year-old child has been stateless since birth as she is not eligible for British citizenship.
Her mothers are from the UK and Bulgaria and the child was born in Spain.
As her British mother obtained citizenship by descent, she is unable to pass it on to her daughter.
The Home Office has refused to issue the child with a passport several times.
Their case was also refused in the Bulgarian courts, who stated they do not recognise non-traditional families.
Jane, the child’s British mother, told The Guardian: “We were shocked that our daughter was denied a UK passport.”
“We knew we would have challenges getting her Bulgarian citizenship, but we didn’t expect that from the UK. We never thought our child would end up with no documents, stateless.”
The mothers brought their case to the the Court of Justice of the European Union (CJEU) and their daughter was issued a Bulgarian passport.
Patricia Cabral, legal policy coordinator at the European Network on Statelessness said: “While UK nationality laws don’t explicitly discriminate against LGBTIQ+ parents, it’s the implementation in practice and the lack of regulation for children who may be stateless that creates these situations.”
The European Commission adopted a proposal earlier this month that stated parenthood established in any EU member state should be recognised by all other EU nations.
However, since the UK has left the EU, the proposal will not affect families where one parent has British citizenship.