Leave it to Secretary‘s Maggie Gyllenhaal to ask the most provocative question on Discovery’s new series Curiosity. On this Sunday’s episode (for mature audiences), the star of the stimulating upcoming film Hysteria hooks up with experts to find out why sex is fun. For a tease, watch our two exclusive clips below. In the first, she narrates an experiment in which scientists are studying brain activity during a female orgasm. “Inside this MRI machine, she’s about to give herself an orgasm in the name of science,” Gyllenhaal says. Thirty different areas of the brain light up when she finally succeeds. In the second clip, she narrates an experiment by a biological anthropologist at Penn State who concludes that women report more frequent orgasms with men of “high genetic quality,” which could mean the female orgasm functions as an incentive for women to select sexual partners with good genes in case they procreate.

Other upcoming episodes of Curiosity will find Robin Williams studying the effect of drugs on our bodies, Samuel L. Jackson surveying how the world might end, Brendan Fraser digging deep to uncover what really lies beneath Egypt, Morgan Spurlock seeing if living as a primitive caveman would actually improve our health, MythBusters’ Adam Savage testing if we can really live forever, and Dirty Jobs’ Mike Rowe revealing the hidden organisms that call our bodies home.