Why do we find twins so fascinating?

And what's it really like to be one?

Five sets of twins get real about the ups and downs of moving through the world with someone who looks exactly like you.

From dressing alike to developing secret languages, Now or Never producer Jessica Singer and her twin sister Nicole kick the show off by answering all your nosy questions about life as a twin.

For first-time parents Kim Miller and Robert Jiang, having toddler twins has been a handful. But Robert’s mom Sufan Lu has jumped in to become a lifeline for Kim and Robert, and a delight to her grandchildren. Find out why all parents of multiples need a nai nai (grandmother) like Sufan in their lives.

Identical twins Niko and Marko Martinovic grew up pulling off pranks together, switching spots on unsuspecting friends and family. Today they've turned those pranks into a full-time job, as the creators and stars of the "Even Out Twins" on YouTube. But ten years in, Niko and Marko are starting to question how constantly assuming the same identity has affected their individuality.

Rory and Camilla Turnbull were born identical twin sisters, but now that Rory has come out as trans they’re navigating life as brother and sister for the first time.

Mercedes Sheen vividly remembers the time she fainted dramatically in the dining hall at primary school. But her twin sister, Michaela Sheen, insists it was she who fainted dramatically that day. These sorts of disagreements are what Mercedes calls “disputed memories,” and it's a phenomenon that happens mostly with twins. Mercedes and Michaela reunite to tell us how this unique twin experience (and childhood argument) led Mercedes to do a PhD on it.

Twin sisters Chantal and Jeannelle Tousignant aren’t just best friends. At the age of 35, they've decided they'll also be lifelong roommates. How a low point in each of their lives caused them to move back in together, and led to a surprising realization they share the same life dream -- one they only want to achieve together.