Smart Meters and Smart electric Meters do put out a bit of radiation that is not all that great for anyone's health.
But actually the smart electric meters do not constantly emit that radiation like cellphone towers and other things do.
The smart meter is only emitting radiation for a few minutes every 6 to 10 minutes or so to send the data to the utility company.
So you're not constantly getting hit with the radiation and the radiation is actually being sent away from your home anyway so it's not likely to harm you when in your home.
Your cellphone and microwave emits way more radiation than a smart electric meter does so smart electric meters are no more dangerous than your microwave or cellphone.
There's also no way to opt out of a smart meter unless you don't want electricity at your home and there's nothing to really worry about when you do have a smart electric meter installed on your home.