A High Court judge has raised concern after a surrogate mother was given "incorrect information" about the identity of the biological father of a baby she was carrying.
The surrogate mother had made an arrangement with a married couple in 2012, become pregnant in early 2014 and thought that the biological father was the husband, Mrs Justice Theis heard.
She had not realised until late in her pregnancy that the married couple separated after making the arrangement - and the father was the wife's new partner, the judge was told.
Mrs Justice Theis, who analysed the case at a family court hearing in London, said she was greatly concerned.
She said, in a written ruling, that the problem was an example of difficulties which could arise when surrogacy arrangements were made.
The husband had provided sperm when the couple made an agreement with the surrogate mother, said the judge.
More sperm had then been provided by the wife's new partner after the marriage broke down.
Mrs Justice Theis said "embryo transfer" had taken place at a fertility clinic in Cyprus and the surrogate mother had given birth to a girl in October 2014.
The wife had said she was initially told by a solicitor that the surrogate mother need not be informed that an embryo had been created from her new partner's "genetic material" - not from her husband's.
She had said she felt "uncomfortable" about giving "inaccurate information" and lawyers had subsequently advised her to tell the surrogate mother.
Mrs Justice Theis said the surrogate mother had learned the identity of the genetic father two months before she was due to give birth.
"It was of great concern to this court ... that a situation had arisen whereby (the surrogate mother) had embryos transferred to her that were different than what she understood to be the position under the agreement she had signed," said Mrs Justice Theis, who sits in the Family Division of the High Court.
"(The surrogate mother) should have been informed of the genetic changes in the embryo prior to it being transferred. The distress this caused to (the surrogate mother) is clearly and powerfully articulated."
The judge said: "This case highlights the difficulties that can occur in this type of arrangement and the need for there to be complete transparency on both sides prior to any significant steps being taken."
Mrs Justice Theis said she had made orders which gave the wife and her new partner parental responsibility for the little girl.
She said the surrogate mother had consented to the making of a "parental order".
The judge said no-one involved could be identified.