Four sisters are pregnant at the same time - and compared the biological quirk to 'Russian dolls'.
First-time mum Kayleigh Stewart, 29, and mum-of-one Jay Goodwillie, 35, are both set to deliver baby boys in May.
Mum-of-one Kerry-Anne Thomson, 41 and mum-of-one Amy Goodwillie, 24, are earlier on in their pregnancies.
The number of young children in their family will double from four to eight, with the addition of two boys for the first time.
Their Christmas get-together will include 22 people, including new babies, partners and grandparents.
The siblings, from Stirling, also have two other sisters, mum-of-one Kim Goodwillie, 27, and Jodi Goodwillie, 21.
Jay's due date is May 11 and Kayleigh is due to give birth 11 days later while Kerry-Anne is due in October and Amy's is in August.
Kayleigh, who works as a dog-walker, said: "All the babies will have cousins the same age.
"Me and Jay were both due on May 22, but her's is now May 11. I'm still quite shocked.
"There will be another four kids this year - it's doubling. I have loved being an aunt and want to be a really active mum. Jay and I found out first, it was a surprise for me.
"Jay had been trying, we were on Facetime and she said 'I've got something to tell you'. I said 'No chance, me too.'
"A few weeks later we decided to tell the family at the same time, with t-shirts. They thought I was wearing a t-shirt for Jay."
They shared a gender-reveal party, and were stunned to find out they were both expecting boys.
Amy, who runs the family guesthouse, announced it at Christmas, and Kerry-Anne, who works in pensions, shared the news in March.
Both women had hoped for another child but wanted to focus on their young daughters' early years first.
Kayleigh added: "We have always been a close family, at one point we all lived together in a house share. We would always steal each other's clothes and make up.
"We live quite close by, about five minutes' walk. It will be good for daycare. Our mum is so excited, she is going to be everyone's birthing partner. There will be a lot of hand-me-downs."
Pregnancy has been quite difficult for Kayleigh and she is looking forward to it being over.
She added: "I'm really looking forward to meting the wee guy to see what he looks like.
"Only four weeks and I can lie on my belly again.
"It is statistically really unlikely to be pregnant at the same time.
"We have quite close periods so I don't know if that is a factor. It's really weird how the body works.
"It's been good being able to say 'do you feel this', especially to Jay as she is at the same stage.
"At the moment there's 18 of us, including boyfriends, husbands and fiances. With the four babies, there will be eight children at Christmas, so 22 people.
"It's like Russian dolls."
Kerry-Anne said: "It's really exciting for the family. I love the fact that the babies will all be in the same class together once they go to nursery and school. I'm sure they will be great friends."
