Bedtime Rituals

Scene:
Me: Just out of the shower, brushing my teeth.
Keith: still in the shower, washing.

Keith: I don't think our soaps should mix. They might make baby soaps.
Sarah: Nah, they won't. Mommy's on protection. And Daddy's sperm can't do the job.
Keith: Oh REEAALLAY?
Sarah: [ sly smile ] Well, do you wanna try it?
Keith: What, make baby soaps?
Sarah: Suuurrre. If that's what you wanna call it.

Please tell me I'm not the ONLY ONE who finds the above exchange funny.

Anyone?