nehusker13 and I were fishing on a like near Brookings, SD. It was colder than a Well Diggers @#$ and I thought I heard a baby crying. I climbed out of my shanty and listened. Sure enough I was right. Over about 75 yards was a small clam style shanty complete with a newborn baby. I personally don't think that 18 months would be a problem if you were more concerned about entertaining them than fishing, but there is a limit. This situation wasn't only bad judgment, it was dangerous. The temp ended up being 15 below with a 15m/h wind. Thats too cold for a baby.