The woman, who gave birth to twin boys following artificial insemination, launched the case in a bid to strip the children’s other mother of parentage.
The case is thought to be the first of its kind in Scotland.
The birth mother, referred to in a newly released court judgment as the pursuer, filed for a declaration of non-parentage against her former partner, the defender.
She brought the case after Nuffield Hospital in Glasgow, the private hospital which helped her conceive, lost paperwork showing her former partner had accepted parental responsibility.
The children’s second mother has no biological connection with the twins, now aged seven.
But the case was rejected by Edinburgh Sheriff Court last month after some claims made by the boys’ birth mother were dismissed as “nonsense”.
The couple were together for almost eight years, and although they were not married or in a civil partnership, they shared a home, a car and holidays together.
The women decided they wanted to start a family together in 2007 - a year into their relationship.
The birth mother tried twice to conceive using a friend as a sperm donor, without medical assistance, but this was unsuccessful.
The twins were then conceived through artificial insemination in 2009 - after three failed attempts.
But the pair’s relationship turned sour in 2014 and they split.
This was the same year Nuffield Hospital admitted it could not find documents signed by the non-birth mother declaring parentage.
In her case, the birth mother claimed she had not been in a stable relationship with her partner when they had the twins.
But Sheriff Wendy Sheehan rejected that idea.
She said: “I did not accept the pursuer’s evidence that the relationship was not a committed one and that it was only a ‘partnership of sorts’.
“The pursuer’s evidence disclosed a level of disappointment and bitterness stemming from the difficulties between the parties in the latter part of their relationship and the breakdown of their sexual relationship.”
She added: “I found the pursuer’s evidence, which was given in an attempt to persuade the court that the parties’ relationship was anything other than a long-term and committed one, slightly baffling.”
The twin’s birth mother tried to claim the defender told her she didn’t want the responsibility of being a parent.
She also told the court she felt pressured to register the children’s births jointly by recording the defender as a parent.
When asked why the second mother was then on the children’s birth certificate, she said she hadn’t thought much about it at the time.
She also said she was “tired after the birth and looking after the boys”.
The Sheriff said her evidence “did not make sense”.
She said had that been the case, the birth mother would not have consented to the defender being a legal parent in the first place.
Sheriff Sheehan said there was “no evidence of any confrontation or influence being brought to bear regarding the registration of the children’s births. “
She ruled there was “sufficient evidence” the appropriate forms, showing parental responsibility, had been signed by both mothers but they had been lost.
And she accepted the evidence before her, from hospital staff and family and friends, which showed the decision to have the twins was a joint one.
The defender was present at the twins’ birth and was at the hospital every day for two weeks afterwards while they were in the special baby care unit.
During evidence, the defender was cited as saying the couple were “very happy, in love and excited about registering” the twins’ birth.
She said she “felt like the beginning of our lives together as a modern family.
“For me it was like a dream come true.
“It was also very exciting to be amongst the first same-sex couples registering our children’s births and becoming legal parents.
“I was so happy that our children were beginning their lives within a secure and solid family unit.”