I've been wearing Leight Sleepers earplugs for over 20 years. I have successfully raised 2 kids to ages 15 and 17 so far, and have always heard what needed to be heard at night. I cannot fall asleep unless there is dead silence. Earplugs help to primarily block low frequency sounds, but they still allow you to hear sudden loud noises or high frequency sounds, as well as someone talking to you. I have photos of me holding my newborn baby, asleep on my glider with earplugs in. I have always woken up when my babies cried and when they got older, walked into my bedroom saying "mommy." I've never slept through an alarm. I hear all that stuff.
The earplugs drown out the sound of our fan so I can actually get to sleep. Yes, I'm such a light sleeper that even white noise keeps me awake.