She can’t be serious
Unfortunately, sex education is either completely removed from most high school curricula or is only designed to terrify teenagers into avoiding having sex as a result of financial limitations and parental complaints. It would benefit everyone to have a thorough education class early on, even though we won’t delve into the politics of other forms of adult-minded education here.
However, it appears that this mother missed out. It is reasonable to be anxious about an unfaithful partner when the newborn looks radically different from either of them. Nevertheless, this woman is unaware that self-deception is impossible.