It does seem that the humor on the Big Bang Theory has grown more sexual and less intellectual after the first several seasons. I was hoping Sara Gilbert's character, Leslie Winkle, would remain as an antagonist for Sheldon. Their bantering once led to this humorous exploration of cosmological theories as analogous with religious beliefs:
From "The Codpiece Topology" episode:
Sheldon: Leonard, you are my friend. And friends support their friends, apparently. So I am withdrawing my objection to your desire to have a relationship with Leslie.
Leonard: Thank you.
Sheldon: I will graciously overlook the fact that she is an arrogant sub-par scientist, who actually believes loop quantum gravity better unites quantum mechanics with general relativity than does string theory. You kids have fun.
Leslie: Hang on a second. Loop quantum gravity clearly offers more testable predictions than string theory.
Sheldon: I’m listening, amuse me.
Leslie: Okay, well, for one thing we expect quantized space-time to manifest itself as minute differences in the speed of light for different colours.
Sheldon: Balderdash. Matter clearly consists of tiny strings.
Leslie: Are you going to let him talk to me like that?
Leonard: Okay, well, there is a lot of merit to both theories.
Leslie: No there isn’t, only loop quantum gravity calculates the entropy of black holes.(Sheldon grunts.)
Leonard: Sheldon, don’t make that noise, it’s disrespectful.
Sheldon: I hope so, it was a snort of derision.
Leslie: You agree with me, right, loop quantum gravity is the future of physics.
Leonard: Sorry Leslie, I guess I prefer my space stringy not loopy.
Leslie: Well, I’m glad I found out the truth about you before this went any further.
Leonard: Truth, what truth? We’re talking about untested hypotheses, uh, it’s no big deal.
Leslie: Oh, it isn’t, really? Tell me Leonard, how would we raise the children?
Leonard: I guess we let them wait until they’re old enough and let them choose their own theory.
Leslie: We can’t let them choose, Leonard, they’re children. (Storms off.)
Leonard: Wait, where are you going?
Leslie: I’m sorry, I could have accepted our kids being genetically unable to eat ice-cream or ever get a good view of a parade, but this? This is a deal breaker. (Leaves.)
Sheldon: Look on the bright side.
Leonard: What’s the bright side?
Sheldon: Only nine more months to comic-con.