
Childbirth is a
NATURAL, beautiful...
The Big Bang Theory Season 7, Episode 11

Yeah! Natural selection at work.
The Big Bang Theory Season 1, Episode 15

Primates such as ourselves
have a NATURAL instinct...
The Big Bang Theory Season 4, Episode 19

But it's NATURAL,
boys having a go beneath the sheets.
Game of Thrones Season 3, Episode 6

It's only NATURAL.
The Big Bang Theory Season 12, Episode 12