I'll throw a spanner in the works here and say I remember this scene -- but, I seem to remember that it wasn't mpreg, but b&j deciding to use a surrogate or adopt a baby.

The more I think about it, the more I think they were planning on surrogacy with Justin as the birth father.

I remember the scene (or dreaming up the scene!) because I don't like Lindsay, and always enjoy seeing her put in her place.

Wish I could remember more.