Revelations - S5-E22
Heimdall: As a race, the Asgard reproduce exclusively through a process of enhanced cellular mitosis.
Samantha Carter: Are you serious? You have no other means of propagation?
Heimdall: No.
Jack O'Neill: Carter?
Carter: They're clones, sir. All of them.
O'Neill: Ah. Well, that answers a few questions.
Heimdall: In fact, for nearly a thousand years we have been physically incapable of achieving cell division through meiosis.
O'Neill: [Confused, looks at Carter] Hmm?
Carter: [Whispering] Sexual reproduction, sir.
O'Neill: Ah. [To Heimdall] A thousand years?
Heimdall: It is usually not something we discuss with other races.
O'Neill: This I understand.
Answer: While the series was undeniably successful, filming it is a long process, taking many months of often long days. Anderson, after several years of doing this, wished to spend more time with his young daughter, who he felt he was neglecting, and requested that his role in the series be scaled back. Ultimately, he decided to leave the main cast altogether and only make occasional guest appearances.
Tailkinker ★