Everyone with parental rights must consent to an adoption, so it’s not the same thing. Parental rights are either terminated or transferred (generally when both parents die at the same time) upon death, so people who are single parents due to the death of the other parent would be the only ones with parental rights. Otherwise the parental rights of the non participating parent have already been severed (though most of the time, they do still have some rights and maintain a financial responsibility, they’re just not doing the actual parenting, meaning they would also need to consent to put the child up for adoption).