According to this page (http://www.geocities.com/krygsman/_sara.htm), Sara Gilbert wrote an episode of Roseanne. For the life of me, I can't figure out which one it is; her IMDB credit does say she was a writer for the show, so it must be true...

She wrote an episode called "Don't Make Me Over"

The girls take Roseanne to the Beauty Box for Mother's Day in hopes of convincing her to let them attend a weekend rock concert.

It was a good episode in the 5th season

She wrote that? I didn't know that. Wasn't she only like 16 at the time?

It aired in the 4th season, bubble yum.

It was the second last episode in the 4th season. Sara was 17 when she wrote it.

She probably just co-wrote it. Sitcoms usually have a writing team, sometimes up to 12 people or more.

I remember watching that episode and in the beginning credits it had Sara as one of the writers. I was so surprised to discover that out.

I'm just speculating here...but I suspect she just came up with the overall concept...or maybe added a few lines to the show herself, like with songwriting...change a word and you get credit (I think, LOL).

She probably sat down and told the other people her suggestions.