[delichon]

  The original Bradford pear tree was ideal for planting because it was thought to be sterile in that it could not reproduce. -- TFA

  John Hammond: There you are. There. They imprint on the first creature they come in contact with. Helps them to trust me. I've been present for the birth of every creature on this island.
  Ian Malcolm: Well, surely not the ones that have bred in the wild.
  Henry Wu: Actually, they can't breed in the wild. Population control is one of our security precautions. There is no unauthorized breeding in Jurassic Park.
  Ian Malcolm: Uh, and how do you know they can't breed?
  Henry Wu: Well that's because all the animals in Jurassic Park are female. We've engineered them that way.

[gweinberg]

One of the more ridiculous concepts in a completely ridiculous movie. The frogs and fish that "change their sex" just change what kind of gametes they make in their splooge. Totally re-plumbing their insides would a completely different kettle of fish.

[kortex]

It's a plot point which drives the entire narrative. If we took out ever sci-fi element that was scientifically implausible, you'd take out a hefty chunk of sci-fi.