My twins were so confused when their uncle came to visit for the first time since he looked just like their dad.

"We have no way to know what the dog is truly experiencing here," Annie Grossman, a pet behavior specialist, told Newsweek.

My sister and I lived in a small town in Iowa in the '80s, and we were known for being identical twins. I had to learn who I really was.

Conjoined twins – identical twins that are joined together. They are extremely rare, and it’s estimated they range from one in 49,000 to 189,000 births, although around half are stillborn, and ...

Conjoined twins – identical twins that are joined together. They are extremely rare, and it’s estimated they range from one in 49,000 to 189,000 births, although around half are stillborn, and ...

That's why fraternal twins don't look identical, and can be boy/girl rather than just girl/girl or boy/boy. The majority of ...

A pair of identical twins have just celebrated their 100th birthday- naming a love of sports as the secret to a long and happy life. Williams Casey — known as Bill — and his twin brother Jack ...

Nature Reviews Genetics - Not-so-identical twins. Monozygotic (MZ) twins have been widely used in studies of human disease, endophenotypes, gene expression and gene–environment interactions.

The author (not pictured) married an identical twin and had fraternal twins. Courtesy of the author I had an emergency C-section and gave birth to my twins early at 35 weeks.

Dr. Emily Hadley, who is a maternal fetal medicine doctor at St. David's North Austin Medical Center, where Ruiz received care, said she's only seen about 10 cases of momo twins in her 14-year career.