By definition, twins are the same age and have the same birthday. However, in the case of twins Sarah and Will Sargent, they were two years apart.

The siblings have gone viral after revealing that even though they’re 18 and 20 years old respectfully and have different birthdays, they’re actually twins.

How is that possible?

Well, Sarah and Will, from Hobart, Tasmania, were conceived on the same day and time with IVF from the same batch of embryos. The only difference is that the embryos weren’t implanted at the same time in the mother.

Will was the first to be implanted and born, while Sarah’s embryo was kept in the freezer for 18 months until she was implanted. So, they’re twins—they were just born two years apart.

Crazy, right? What’s even crazier is that the two only just found this news out from their parents a couple of years back—when Sarah was 16 and Will has 18.

Sarah shared her story on TikTok, which has received over nine million views. “My parents had children using IVF. Mum produced lots of eggs with each IVF cycle,” she said in the viral video. “The clinic attempted to fertilize all the eggs and had a reasonably high success rate. The embryos are examined and the strongest two are used first.”

“One of these embryos went full term and that’s when my brother was born,” she continued. The other embryos are frozen so that they are available for implantation in the future. I was one of these embryos and I was defrosted and implanted around 12 months after my twin brother Will was born, in January 2001. I was born in October 2002, 21 months later.”

The two are still considered twins because they were created in the same comb. It was just that they weren’t implanted at the same time. “’Had our embryos fertilized naturally, my brother and I would have been non-identical twins born at the same time,” she explains.

When Sarah’s dad was driving her to school two years ago, Sarah said that she thought she was adopted because she was completely different than everyone in her family—and that included Will.

“My dad was driving me to school, and I was saying that I was convinced I was adopted because I thought that I looked and acted different than everyone else in my family, especially my brother,” she explains. “He then said ‘well, I know for a fact you aren’t adopted because Will is your twin brother.” The parents said they didn’t want to to break the news to the kids until they were old enough o understand it.

“It has really taken me up until a few of months ago to properly accept it and I am still amazed by it to this day,” she says.

To hear her entire story, check out the viral TiKTok video below!

@sar_sarge Reply to @julesss431 #greenscreenvideo part 2 explained! #ivf #ivftwins #twins #part2 #ivfbaby ♬ original sound – Sar sarge

Did you know that twins could be two years apart? What do you think of Sarah and Will’s story?