She was only Superman’s daughter, but she made me a Man of Steel!
Come to think of it, so did the machinist’s daughter.
She was only the athist’s daughter but she certainly believed in the Second Coming.
It was only a thread, but it loomed in the wrong forum.
Off to MPSIMS.
She was only a pilot’s daughter, but she always kept her cockpit clean.
And a classic one about Margaret Thatcher:
She was only a grocer’s daughter, but she taught Sir Geoffrey Howe.
She was only a saggar maker’s daughter, but she was good at putting her knockers on my bottom*.
She was only a Doper’s daughter, but she knew what to do with a post!
Better still:
She was only a mortician’s daughter, but she knew how to bury the old stiff!
She was only a farmer’s daughter, but boy did I like to plow her.
It is. They used to say it back in my mom’s “day” (1930s or so).
She was only a Magician’s daughter, but boy did she know how to vanish a wand.
She was only a Judge’s daughter, but she knew how to introduce a motion in the chamber.
She was only a Civil Engineer’s daugher, but she knew how to stop traffic.
She was only the President’s daughter, but she knew how to come in the Oval Office.
She was only a PC repair technician’s daughter, but she knew how to handle a hard drive.
She was only a mortician’s daughter, but anyone cadaver.
I’m crying here. I love these!
She was only a UPS driver’s daughter, but my package always came on time.
OK, I should be working. . .
She was only Mary’s daughter, but there was always something about her.
She was only the drummer’s daughter, but man, how she could bang you.
She was only the electrician’s daughter, but how she would turn me on.
She was only a redneck’s daughter, but his wife as well.
OK, back to work.
She was only a clarinetist’s daughter, but she sure knew how to blow wood!
She was only a potter’s daughter, but she had perfect jugs!
She was only a boilerman’s daugher, but things got steamy real fast!
She was only a streetcleaner’s daughter, but I got swept away!
She was only an ornithologist’s daughter, but could she swallow!
She was only the President’s daughter, but what a Bush!
She was only a secretary’s daughter, but she really knew how to take dick-tation.
She was only a psychiatrist’s daughter, but she loved to lay me on her couch.
She was only Dick Cheney’s daughter, but she’s not overly fond of Dick.
Nice one 
And on that theme…
She was only Bill and Hillary’s daughter, but boy what a pair of boobs!
She was only Woody Allen’s paramour’s adopted daughter, but…