We were born on the same day of the same year, and we have the same mother and father. But we're not twins, How??

Question

"We were born on the same day of the same year," said Betsy.
"And we have the same mother and father," said Patsy.
"But we're not twins," said Betsy.
Can you explain?

Answer 1

Actually, you two were wrong, there actually is a third child at the pack.

Answer 2

Yes you could born on 15 Jan and 24 Dec of 2015 both have same day Thursday with same parents

Answer 3

They are dutch twins, in otherwards born less than twelve months apart but in the same year.