06/01/2012 at 12:00 PM EDT
Neil Patrick Harris
and David Burtka's twins, Gideon and Harper
, welcomed a very special visitor recently – Oprah Winfrey
"They're super healthy and they're happy," Harris says on Oprah's Next Chapter
of the 19-month-old twins, who were born via surrogate
in October 2010.
In Harris's and Burtka's telling, the twins' conception was a miracle of modern science, involving two embryos – one for each of them
– and a surrogate. ("She was more like the oven," according to Burtka.)
The proud papas knew the surrogate
but the egg donor was anonymous, though they were able to research her personal and medical history beforehand.
Harris tells Winfrey they "lucked out" that both of the embryos took.
And the twins are starting to develop distinct personalities. Gideon is "the shy one," according to Burtka, but both love the water and are taking swimming classes in preparation for the summer.
Oprah's Next Chapter
with the Harris-Burtka family airs June 3rd at 9 ET on OWN.