When Daphna and Alexander’s daughter was 3 months old, they found out they took the wrong baby home.

Imagine welcoming your baby into the world after a long IVF journey, hearing them cry for the first time and holding them close. You're happy.

But, as they grow, a thought continues to nag at you: your little one doesn't look like anyone in your family. The IVF clinic couldn't have made a mistake… that doesn't actually happen, right?

It's rare, but for two families in California, that was their reality.

After three years of trying to fall pregnant with their second child, Daphna Cardinale and her husband Alexander turned to IVF. They welcomed little May into the world, but she didn't look anything like Alexander, a man of Italian descent with fair hair and light brown eyes, or Daphna, a redhead with Ashkenazi Jewish heritage.

Little May had a much darker complexion and jet black hair.

"She looked really different than us, but she felt so familiar to me because I carried her and I birthed her," Daphna told People.

After weeks of being unable to shake the feeling something was off, the couple ordered a DNA test in November 2019 and sent off their samples, per the New York Times.

The results arrived and said: "99.9 per cent likelihood, not a match for the father." But surely Daphna was at least a match then?

"99.9 per cent likelihood, not a match for the mother," the results said.

Watch: Meet the baby born from a 27-year-old embryo. Post continues below.

The news rocked the couple. What do you mean the baby they'd spent the past two months showering with love and adoration wasn't genetically theirs? Could they lose May to her genetic parents?

Then there was the guilt.

"We didn't want to be those people who were so desperate for a baby that we were going to deprive someone of theirs," Daphna told the Times.

Daphna and Alexander contacted a lawyer, who informed the clinic.

On December 6, they discovered the lawyer had found May's parents, who lived just 10 minutes away. But there was more — the other family had a baby the same age as May, called Zoë, and she was Daphna and Alexander's genetic child. Zoë's parents, Annie and her husband, were equally rattled by the mix-up.

On Boxing Day, the two couples met for the first time, buzzing with nerves as both worried about what they should do. Do they swap their babies or keep them? It's an unimaginably difficult decision, especially when both babies have older siblings who've welcomed them into their loving arms.

When the couples met, it was awkward, but they soon realised they each felt as lost as the other.

Finally, Daphna voiced what they were all thinking: "What are we going to do?" They had an idea, but could they even say it out loud? Eventually, Annie's husband said they should switch, and they wept, per the Times.

But how do you navigate switching babies, and how do you tell their siblings?

Their siblings had already gotten to know each other. Image: Getty.

The couples started with an initial meeting and then regular visits, switching to spending time with both babies.

Daphna cried the first time she was alone with their genetic baby. She knew she loved her, but she also loved May… how could she give her up?

Adjusting to life with their genetic babies wasn't easy. Each couple loved their baby but still longed for the other, wondering how you hold space for both girls and if that's even fair.

But what if there was a way to have both?

The families were struggling and leaned on each other. During the pandemic, they decided to form a pod and grew even closer, as the couples and the four children found a place for each other in their own way.

Now, they're deeply intertwined.

At five years old, May and Zoë consider each other sisters and hang out all the time.

"There's no book for this. There's no person to give you advice, so we ended up just sort of huddling together, the four of us, and it's a blessing that we all are on the same page," Alexander told People.

They've spent every birthday together since then as basically blended families.

Daphna and Alexander ended up suing the IVF clinic for medical malpractice and settled out of court in 2022.

Their parents say it's not a happy ending, but told the Times it's the happiest ending possible.

Feature image: AAP.