We learn that Kal-El is a rare natural born Kryptonian.
What about Kara?
I'm not familiar enough with the continuities to specify, but please use the same continuity that explains Kal-El's birth.
In the CBS TV show, Supergirl, we have no evidence that Kryptonians are anything but natural born. The only knowledge we have about their births is that twins are extremely rare, making Alura and Astra an oddity. However, even this seems to suggest natural births.
Only in the Zack Snyder DC cinematic movies, Man of Steel, Batman v Superman: Dawn of Justice and the upcoming related releases, does the idea that Kryptonians don't give birth, but rather clone or manufacturer themselves, exist.
Both versions of Krypton, Supergirl's and Man of Steel's are completely separate continuities.