Knocked Up

Ben Stone (Seth Rogen) is a 23-year-old slacker who is in the process of establishing FleshOfTheStars.com, a website that lists the exact moment in time at which nude scenes with famous actresses occur in films. Alison Scott (Katherine Heigl) is a responsible young woman who works at E! Television Network. Although she is on the career fast track, she lives in the pool house behind her sister Debbie's home, and plays an active role in helping her and her husband Pete raise their daughters.Alison and Ben find themselves at the same club where she is celebrating her promotion at E! with her sister. They begin drinking together, and she invites him back to her pool house. The next morning, they learn that they have very little in common. Eight weeks later, Alison begins feeling very sick and comes to the conclusion she is pregnant, and she contacts Ben. She tells Ben she is pregnant and that she has decided to keep the baby. Ben's initial response of shock and anger mixed with Alison's frustrations creates tension, resulting in Ben agreeing to take Alison to the OB/GYN to confirm the pregnancy.After the pregnancy is confirmed, Ben says he will be there to support Alison and help her through it. She and Ben begin spending more time together and become very close. Ben awkwardly but sweetly proposes to Alison, saying he just wants to do the right thing. Alison is touched by the gesture, but thinks it's too soon for marriage. Meanwhile, Debbie begins to suspect Pete's late night jaunts out of the house to see a band for his record label, are really a cover for an affair. But when she tries to prove this, she later discovers Pete's actually part of a fantasy baseball league. Debbie refuses to speak to Pete thereafter.On the way to the gynecologist's office, Ben and Alison begin quarreling. She kicks him out of her car onto the road, and heads to the doctor's alone while blaming her hormones. Ben walks the rest of the way to the gynecologist's; Alison still doesn't want to see him and asks Ben to leave. Alison says she doesn't want to end up like Debbie and Pete, they have a heated exchange, and Ben storms off.Fed up with their respective situations, the two men take off for a road trip to Las Vegas, where they indulge in psychedelic mushrooms and watch Cirque du Soleil. While hallucinating, they have a revelation: They should be back in LA taking responsibility. Debbie and Pete's reconciliation is evident at their daughter's birthday party, but when Pete confesses to his wife about have done mushrooms, Alison hears and refuses to speak to Ben, who tries to reconcile. Ben goes out to get a job as a web designer, gets a decent apartment, and sets up a baby room in his apartment, all the while spending less time partying with his friends and more time reading the books he purchased with Alison about pregnancy, that he'd lied to Alison about having read.Alison goes into labor and tries to get a hold of her doctor. Unable to contact him, she calls Ben, who takes her to the hospital where the two reconcile, and they joyfully welcome the birth of their daughter. A few days later, Alison, Ben, and the baby are heading back home. They decide to live in Ben's new apartment, and the end credits show the young family living happily ever after and celebrating their daughter's first birthday.

Question: How old is Seth Rogen's character in the movie?
Answer: 23 years old