Sexual transmission of Hep c is rare, even more so female to male.
Sexual transmission, when it does happen, is almost always male to female.
fyi
Apologies; I misread you. Is this woman treating in the US? If so, the standard of care includes the drug ribavirin; I don’t know why they would treat her without it. To avoid confusion, this should be run through her doctor to rule out any misunderstandings.
Bill
Hep C is rarely transmitted sexually; especially in the absence of trauma. Your son has little to worry about in terms of transmission. However, the young lady should DEFINITELY be using barrier contraception if she is engaging in sex while on treatment.
The drug ribavirin can be damaging to the fetus; she is risking serious birth defects and death to her potential child. This is serious enough that a ribavirin pregnancy registry has been initiated; please have her discuss this with her treating physician immediately so corrective action can be taken—
Bill