Say that Mary Moe is pregnant, HIV positive, and planning to take her child to term. Assume also that medical treatment for the HIV during pregnancy can substantially decrease the risk of her communicating the HIV to the soon-to-be-born child. (As best I can tell, that's factually accurate.)

Say also that Mary Moe is infected with some other disease — call it German Measles 2 — that risks causing birth defects in the children of other pregnant women who come into contact with Moe. (The hypothetical disease would differ from traditional German measles in that it would be persistent but asymptomatic in the carrier; in this respect, imagine Moe as a Typhoid Mary for this disease.) Assume also that medical treatment for German Measles 2 can substantially decrease the risk of Moe's communicating German Measles 2 to other women's soon-to-be-born children.

I take it that, by analogy to the vaccination cases, the government may force Moe to take the medical treatment for German Measles 2 (am I right?), to minimize huge health dangers to the soon-to-be-born children of others. True, this is an intrusion into Moe's bodily integrity, but your right to bodily integrity must yield when your body is threatening the spread of disease to others.

If so, can it really be the case that the government nonetheless may not force Moe to take the medical treatment for the HIV, to minimize huge health dangers to her own soon-to-be-born child?

Is Moe's bodily integrity sufficient to justify the harm to the life and bodily integrity of her child — not just to a potential person (which is how the law conceptualizes the fetus before viability), but to a real person who will be born, and who may well be sentenced to a short life and painful death because of Moe's communicating the disease to him?

Say that Moe's child grows up to be, say, ten, but is clearly dying by then. She's not just a fetus or even an infant. She can talk, and ask questions. Here's how the conversation goes:

Child: "Why am I dying?"

You: "Because you got a deadly infection from your mother. Your mother could have taken steps that may well have saved your life, but because of her idiosyncratic view of medicine, she chose not to."

Child: "But wait, why didn't someone stop her from doing this to me?"

You: "Oh, we couldn't do that: She had a constitutional right to infect you with a deadly disease, with no interference from anyone else."

Child: "So if someone is walking around with a communicable disease that would cause birth defects in other people's children, he has a legal right to keep doing that."

You: "Of course not; we could mandate that he be vaccinated, or otherwise treated. But that's only when he's infecting other people's children. When a women is infecting her own child who's still in her womb, she has a constitutional right to do that."

Can that really be right?

[UPDATE: Correct a couple of errors in paragraph 2 -- thanks to the commenters for pointing them out.]