One of my villagers was nursing a baby for quite a while. When I turned the game back on, she was standing at the science table researching, but was still holding the baby. Is this a glitch? Will she ever drop the baby?

I think this has been termed as one of those harmless oddities. Occasionally the nursing mothers seem to get so attached to their bub, that when they go back to work, they 'look' like they are still nursing. The baby should be running around in the village though.

I think during testing, we found that when she starts lifting the basket up to harvest, the baby disappears, but I am not sure how quickly this happens when researching.

That's one of the bugs. Mayby a baby is grown up to 2 year old. But mom holds a baby in the screen.(Only in the screen!!) Why don't you move mom with stylus? And then a baby will be gone.

Yes, this is a small glitch in the timing of when the baby graphic is 'removed' from the mom. The toddler is, indeed, running around the village and the 'baby' will be gone if you interrupt the mom or she starts performing a task that requires a different graphic (gathering food, doing laundry, etc.).

My female scientists always conduct research with their babies in tow. I found that a two year maternity leave was simply too long and so, by village proclamation, I have decreed a 2 hour maternity leave. Goggles are issued to the babies. No harm done.