A SINGAPOREAN woman may fail to block her ex-husband's access to her two children - even if she can prove he is not their biological father.

She had fled the United States with her sons, a pair of 10-year-old twins, to come back here to join hands with the children's biological father to make an application to the Family Court for her to be granted sole custody of the boys.

But the court here has ruled that because the twins were born while she was married, her ex-husband is technically their father. So he has a right to have access to them.

That he is not their biological father might well be irrelevant.

These details emerged in a closed-door hearing yesterday in the Family Court, where written judgment grounds were issued.

Under the Children and Young Persons Act, none of the parties can be named to protect the identities of the children, who hold US and Singapore passports.

Meanwhile, the woman's former husband is insisting that he has as much right as her to the children, and has asked the Family Court here to allow him to intervene as a party seeking to set aside the Singapore application.

With her having breached a US court order on custody of the children, who she is supposed to share with her former husband, he also wants a hearing to seek court approval for the boys to be sent back to his care, in compliance with the Los Angeles court order.

Yesterday, he won a victory of sorts.

District Judge Jen Koh upheld his right to intervene in the court order application jointly sought by the woman and the biological father. She also threw out the woman's move to strike out the ex-husband's suit, which means his suit will now go for a full hearing.

The judge ruled that the ex-husband had a right to the children, although he is not their biological father. This comes from the twins having been born while he was married to the woman.

The pair wed in November 1999. In 2005, divorce proceedings started.

The boys are thus his legitimate children - unless it can be proved that the couple had no access to each other at the time she became pregnant.

But, Judge Koh noted, the woman had not raised the access issue in her request to the Family Court for sole custody.

The woman's strategy was, rather, to use the result of a paternity test taken by the biological father to rule out her ex-husband as the father.

But this cannot hold here because the law in Singapore does not provide for the test to be used this way.

And, Judge Koh further noted, two days have already been set aside for a trial on the paternity issue in the US, the trial from which she had fled.

'On all scores, the twin boys are children of the marriage, even if the marriage had been annulled and even if the marriage is not valid,' Judge Koh said.

The woman will now have to convince the Family Court here at a full hearing why the case should not go to the US.

Judge Koh said the woman had commenced proceedings to challenge her ex-husband's custody rights in the US, and in so doing, had submitted to the jurisdiction in the US.

Among other things, the woman said through her lawyer that the twins did not want to see her ex-husband.

To this, Judge Koh pointed out that the woman's ex-husband was the only dad the twins have known, and they spent a good half of their lives in the US, compared to only four months here.

The ex-husband's lawyer here, Mr Foo Say Tun, argued that the man was named as the father in the twins' birth certificates.

This article was first published in The Straits Times.