WHEN Casey O’Connor lost her mum, the first person she turned to for help with her grief was her cousin, Alana.
The pair had been inseparable since they were children, and Alana and her mum were her pillars of strength.
But then in 2020, Casey was hit by a bombshell – her mum had had an affair with her sister’s husband and Alana was actually her half-sister.
The man she had known her entire life as her uncle was, in fact, her biological father.
A DNA test confirmed it in February 2025.
Casey, 37, says, “Coming to terms with it has been an ongoing process, but there has also been something unexpectedly beautiful about the discovery.
“One positive to come out of this is knowing that my childhood best friend was actually my sister the whole time.
“It has explained our strong bond and brought us closer on a whole other level.”
Casey and Alana were called ‘two peas in a pod’ by their friends and family.
Casey says, “Our mums were sisters and we lived next-door to each other. If I wasn’t at her house, then no doubt you’d find Alana at mine.
“We even looked alike, and were forever being mistaken for twins.
“It was a comfort having a bestie so close by, especially as life had been tough.”
Alana’s dad, Bruce, had died in a motorcycle accident when the girls were young.
Then, soon after, Casey’s mum, Linda, was diagnosed with an auto-immune disease.
Casey says, “It meant she was often unwell, but Alana – and her mum, my aunt Donna – were always there for us.
“Sadly, as the years passed, Mum deteriorated and when I was 27, in 2017, she passed away.
“It was devastating, but I was relieved she wasn’t in pain any more.
“The family rallied around and Donna was a huge support, organising the funeral.
“I felt so lucky to have her and told her often. “I’ll always be there for you,” she promised, which was lovely.’
Then three years later, in 2020, Alana called Casey while she was at work.
Casey says, “It wasn’t unusual. We spoke most days, but this time, Alana sounded different.
“She asked me to go somewhere quiet as she had something important to talk about.
“Alana revealed that my aunt Donna had told her something crazy – that she thought we could be half-sisters. I was stunned.’
Alana explained to Casey that her mum had suspicions that Casey’s mum had slept with her dad, Bruce.
Casey says, “My mum had been staying with them when she fell pregnant – but all I could do was laugh.
“It was so far-fetched, I just didn’t believe it was true.
“I wanted to bring it up with Dad but I loved him to bits and didn’t want to upset him.
“It just seemed mad that my mum would have an affair with her sister’s husband.”
For the next few years, Casey tried to put it to the back of her mind, but it niggled at her.
But it wasn’t until 2024, when she was 34, after being diagnosed with Premenstrual Dysphoric Disorder (PMDD) – a severe hormone-related mood disorder – and starting therapy, that Casey felt ready to revisit the rumour.
As she underwent medical testing and began looking more closely at her family health history, she realised there were significant gaps in what she knew about her biological background.
Wanting answers for both her health and her own sense of identity, she decided it was finally time to uncover the truth.
She says, “I sat down with Dad and said, “Alana told me Mum might have had an affair with Uncle Bruce and that he might be my biological dad.”
“To my surprise, he nodded seriously and said he’d suspected it for a long time. I was stunned.
“He explained that the timing around my conception had been a bit unclear, because Mum had been staying with Donna.
“I told him he was still my dad no matter what – but we both wanted answers.
“We ordered a DNA kit online, then sent off saliva samples.
“For the next eight weeks, we were tense as we waited.”
In February 2025, Casey got the results – and it confirmed that she and her father were not a match.
She says, “Although I’d suspected it, it was still a massive shock.
“I rang to tell him the news and he said, “Nothing changes at my end. You’ll always be my daughter.” I told him I loved him. I was so tearful.”
Casey told Alana the news and she also took a DNA test and the pair opened them together when they arrived a few weeks later.
Casey says, “The results showed we were a match – Alana was my sister!
“For a minute, neither of us said anything.
“We knew we had to speak to the family about it, as it was such a bombshell.
“We arranged for everyone to meet at my aunt’s house as I mulled over the truth.
“Donna and my mum had been best friends, and Donna had barely left her side while Mum had been in hospital.
“How could Mum have done something like this to her?
“It hurt knowing that some of our questions would always go unanswered.
“And I was worried how Donna was going to feel now that her suspicions had been confirmed.
“But the moment I arrived at the front door, she pulled me in for a hug, which was a relief.
“Of course, it made it harder not being able to discuss it with Mum and Uncle Bruce, but I told Donna I felt resentment towards Mum.
“She was very forgiving though and said, “People can make mistakes. I forgive her – and Bruce.”
“I was blown away by her compassion.”
Casey felt as though the news brought the family closer.
She says, “My dad and I spent even more time together, walking my dog and grabbing coffee.
“As for Alana and me, we’re as close as always.
“She says she doesn’t feel like we missed out on being siblings, as we’ve been like sisters our whole lives, and she’s right.”
Casey adds, “Today, I’m really open about our family secret. I’m not ashamed.
“Our DNA discovery is just a part of our family history and now the dust has settled, our bond is even tighter than ever before.”
