A same-sex couple is believed to have made medical history after they both carried the same baby in a 'priceless' experience.

Ashleigh and Bliss Coulter, from Mountain Springs, North Texas, underwent the revolutionary fertility treatment Effortless Reciprocal IVF.

The procedure, which allowed them both to be involved in bringing their child into the world, is half the cost of traditional IVF at $8,500 (£6,600).

Eggs were taken from Bliss, 36, and fertilized with donor sperm in the lab.

The embryo was then placed inside Bliss, who acted as an incubator for the first five days, using a plastic device that resembles a champagne cork.

Bliss did not want to carry a child, so the embryo was then removed and placed in 28-year-old Ashleigh.

And in June this year, their 'perfect' son Stetson was born healthy at 8lbs 4oz.

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Same-sex couple Ashleigh (right) and Bliss Coulter (left) made medical history after they both carried the same baby in a 'priceless' experience. Pictured with their five-month-old son Stetson, both wanted to be involved in bringing their child into the world

'Perfect' Stetson was born healthy at 8lbs 4oz last June after just one round of specialist IVF

Ashleigh and Bliss met six years ago and married in June 2015.

Although they both hoped to one day have children, Bliss wanted a baby that was biologically hers but did not want to be pregnant.

Same-sex female couples usually have children via a sperm donor with one woman carrying the baby and the other adopting it.

However, both Bliss and Ashleigh wanted to be involved.

They first learned about Effortless Reciprocal IVF when a friend recommended they watch a news clip about the fertility specialist behind the treatment, Dr Kathy Doody.

The couple made an appointment in 2016 with Dr Doody, from the C.A.R.E Fertility Clinic in Bedford - between Fort Worth and Dallas.

Effortless Reciprocal IVF, currently only offered by that clinic, involves fertilizing an egg with a donor's sperm in a device called an INVOcell capsule.

Eggs were taken from Bliss (pictured with Stetson) and fertilized with donor sperm in the lab. The embryo was placed in Bliss' vagina, which acted like an incubator, for the first five days

This device, made entirely of plastic, is then placed in a woman's vagina, which keeps the embryo warm and removes toxins, like harmful gasses.

In traditional IVF, the embryo is incubated in a laboratory before it is transferred to the woman's uterus.

Usually, Effortless Reciprocal IVF involves the same woman donating her eggs and then carrying the embryo.

Because the egg and embryo came from Bliss and were then put in Ashleigh, this is a unique medical case. Dr Doody believes it is the first of its kind.

She told MailOnline: 'What makes this so special is that it’s the first time that two women have actually carried the pregnancy of their child together.

'Each person played an active role in the pregnancy aspect of their baby, which is different than normal or traditional IVF.'

Dr Doody revealed Ashleigh and Bliss were the first, but not the only, couple that have carried the same baby using Effortless Reciprocal IVF.

She said another unidentified couple in their thirties had given birth to a ‘healthy baby girl a few weeks ago’ after undergoing the procedure.

The embryo was then removed and put in Ashleigh (pictured with Stetson) because Bliss did not want to carry a baby through pregnancy

WHAT IS EFFORTLESS RECIPROCAL IVF? Effortless IVF involves fertilizing an egg with a donor's sperm in a device called an INVOcell capsule (pictured) This chart shows the cycle from egg retrieval and fertilization into the INVOcell, then back out to lab testing before re-implantation Effortless Reciprocal IVF involves fertilising an egg with donor sperm in a device called an INVOcell capsule, which is made entirely of plastic. This device is then placed in a woman's vagina, which keeps the embryo warm and removes toxins, like harmful gasses. This skips the step of traditional IVF, which sees the embryo incubated in a laboratory and can prove costly. Usually, in Effortless Reciprocal IVF the same woman donates the eggs and carries the embryo. Same-sex couple Bliss and Ashleigh Counter, from Mountain Springs, North Texas, made medical history, when they carried the same baby. Eggs were taken from Bliss and fertilized with donor sperm in the lab. The embryo was then placed inside Bliss using the INVOcell capsule, which resembles a champagne cork. Bliss did not want to carry a child, so the embryo was then removed after five days and then frozen until Ashleigh had undergone the necessary hormone treatment to carry a child. Ten days after the treatment began and the embryo had been transferred to Ashleigh's uterus, she discovered she was pregnant. The process costs around $8,500 (£6,600) – making it more than half the price of traditional IVF in Texas, where one cycle can cost up to $20,000 (£15,600). It is currently only offered Dr Kathy Doody, from the C.A.R.E Fertility Clinic in Bedford - between Fort Worth and Dallas. The INVOcell device is then placed in a woman's vagina, which keeps the embryo warm and removes toxins, like harmful gasses The incredible device has an uncanny resemblance to plastic champagne cork Advertisement

Dr Doody and colleagues harvested Bliss’s eggs and fertilized them with the donor sperm almost immediately after.

This was transferred into the INVOcell device and Bliss carried it inside her for five days, until it became a blastocyst.

Doctors then came back and removed the embryo and froze it until Ashleigh had undergone the necessary hormonal treatments to carry a child.

When Ashleigh started on her period, she was given estrogen tablets and then given a bumper dose of progesterone.

They then transferred the single embryo back. Just ten days after the treatment began, Ashleigh discovered she was pregnant.

'Bliss always jokes she has golden eggs,' she told ABC News.

Speaking of her son's birth in June this year, Bliss said: 'The moment he was born, I just thought to myself, "I felt like I was the most blessed person in the whole world" because he was just perfect in every way.'

Although Ashleigh carried Stetson, she believes Effortless Reciprocal IVF allowed her to share the experience with Bliss.

'When I look at him I get to see my wife. It's priceless,' she said.

Though Bliss says she is more than happy with just one child, Ashleigh is convinced she can talk her wife into having another - and they have two frozen embryos on stand-by.

Dr Doody believes Effortless Reciprocal IVF allows same-sex female couples to have a unique bond with their babies and makes for a more 'natural' pregnancy.

She added it can be cheaper than alternative fertility treatments due to the vagina acting as the incubator, rather than having another step in the laboratory.

The process costs around $8,500 (£6,600) – making it more than half the price of traditional IVF in Texas, where one cycle can cost up to $20,000 (£15,600).

Bliss said she felt like' the most blessed person in the whole world' when Stetson, pictured at four months, arrived. Ashleigh said she sees her wife every time she looks at her baby's face

Although Bliss is content with just one child, the pair have two frozen embryos on stand by. Ashleigh believes she will be able to persuade her wife to go through IVF again