Wow, hjbau – it never occured to me until you just pointed it that it is very likely that whatever landed Emma in jail was probably done with or as a result of her relationship with Henry’s father. That would explain her not wanting to let Henry know much about his dad. I always just assumed that it was because his dad was a loser who was probably married and ditched her when she got pregnant or something but I think your theory is right. She also probably doesn’t want Henry to know all the details of why she ended up in jail – giving Henry more info about his dad would likely let Henry know more info about her colorful past than she would want him to be aware of.