The Ministry of Interior could apply to the court to annul a marriage under a "public interest" defense if one of the participants changes their sex. However, the exact meaning of "public interest" is unknown.
Estonia's Family Law Act does not allow same-sex marriage but a union does not become invalid if one of the participants undergoes a sex change after taking their vows.
In reply to a question on the subject from the Ministry of Interior, Tõnis Saar, secretary general of the Ministry of Justice, said according to the law a marriage can only be annulled on the request of a spouse or public interest.
However, officials told ERR the exact definition of "public interest" is not known.
"Each specific case must be considered by itself," Mari Käbi, an adviser to the Department of Population Operations of the Ministry of the Interior, told ERR.
The power also lies with the courts, not the minister, she said.
Saar said: "During the last five or six years, significant changes have taken place in society, as a result of which it can no longer be said that the marriage of a same-sex couple is contrary to Estonian public order."
He said the Minister of the Interior has the right to turn to court if one of the spouses decides to change their sex and demands the marriage be annulled. However, he has no obligation to do so.
"If the spouses met the preconditions for entering into a marriage at the time of entering into the marriage, but one of them later changes his or her sex, then it is not automatically an invalid marriage, but there is a possibility to annul the marriage," Saar said.
Käbi said this is not a big problem in Estonia.
"There are several couples in Estonia whose marriage has turned into a same-sex marriage as a result of the gender reassignment of one spouse, but there have been less than 10 couples," Käbi said.
Kertu Laado, a public relations adviser at the Ministry of Justice, said the matter is related to the Ministry of the Interior so it must decide when it is right to turn to the court.
"If a marriage has been entered into between a man and a woman, but later the circumstances have changed, then the marriage has been validly entered into and it cannot be automatically be annulled, as the marriage has far-reaching legal consequences," said Ladoga.
Editor: Helen Wright