If both sets of parents are ok with it, then presumably they have had the contraceptive chat. If they haven't, then I'm not sure it's your place to do so. Having said that, it comes down to whether you trust your grandson, 16 year old boys being what they are, and whether you are comfortable with the situation. If not, it's your house, so your rules. You are not being unreasonable, especially given their ages.
Being asked for an honest opinion



