So the thought of Charlie being a dad is what this episode is about. An ex-girlfriend has a kid who looks remarkably like Charlie. This lead to huge laughs and hilarious situations for Charlie. Charlie learns that a condom isn't 100% effective after a rather funny, swaying off topic, talk with his chemist. The scene with all the flashes of Charlie being a dad I found rather good. I reckon Charlie would make an awesome dad.
I thought they could have dragged the plot out more instead of ending the whole Charlie having a kid storyline ending there.
Good ratings as well with Viewers: 14.93 million (#2), A18-49: 5.3/12 (#1t).