Meet the woman who is sleeping with her sperm donor: How a desperate quest for a baby led to an unlikely union

Multiple trips to fertility doctors, three miscarriages and $60-$70,000 out of pocket, Tanya was left with little choice: if she was going to become a mother, she would need a free sperm donor.

But for the 39-year-old, the formal process of searching for a suitable candidate on the Free Sperm Donor Register turned into something far from expected – a blossoming new romance.

And, despite the relationship, Tanya is determined to be the only legal parent if she does eventually have a baby.

Tanya sperm donor romance 20/20

'Crazy': Tanya, 39, turned to a free donor site to help her finally become a mother – and was astonished to fall into a relationship with the potential candidate

Having fallen pregnant at just 19 and given up her baby for adoption, Tanya had always wanted to be a mother.

Speaking with ABC's 20/20 programme, the financier revealed that a six-year relationship ended at the age of 36 after her partner revealed that he did not want children.

'I've wanted to be a mom since I was a child,' she told the show. 'I just loved children my whole life… I didn't want to take the chance of never being a mom.'

Turning to the FSDR, Tanya trawled through lists of men willing to contribute free samples.

Having found a match that caught her eye and built up an email and phone relationship with the man, Tanya met with the prospective father of her child – only for the meeting over dinner and a glass of wine to quickly turn into more.

Tanya sperm donor romance 20/20

Trawling: having searched for suitable candidates, Tanya spent weeks emailing and speaking with the man over the phone before finally meeting over a 'date'

'We were both shaking as we were lifting our wine glasses,' she recalls. 'For us, it actually turned out to be a date.'

She is now in a relationship with the donor and believes she has 'hit the jackpot.'

'I wasn't on that website to find a boyfriend or husband or a father of my child, I was on the website to find a wonderful person that was willing to provide me free sperm,' she told 20/20.

She is astonished by the 'crazy' serendipity of the union.

'I never imagined that I would have gone on this website and found someone so wonderful.'

Sperm approaching egg

Donor only: Tanya says she wishes to remain the soul parent if she has a baby

As for becoming pregnant, the couple clearly share the same goal – though Tanya is clear that she wishes to be the baby's only legal parent.

'People have one-night stands and they have babies all the time. I made an adult choice and he and I have come together for a common reason to do this.'

The hope for Tanya is that by becoming a mother, she may at last be able to right the ill feelings she has had since giving up her first child.

'I have a hole in my heart. If I could have another biological child, that I could have the chance to be her mom, it would at least make me feel a little bit better,' she said.

Tanya is clearly realistic about her options, holding her cards close to her chest. 'I'm not sure if it'll be forever but we will definitely have a special bond forever – if I get pregnant.'

And, failing pregnancy yet again, Tanya is keen to adopt. 'I'm a fighter and I'm not ready to give up… I just hope that the end result is me being a mom,' she said.

Watch the story in full on ABC's 20/20 this Friday at 10pm.