Yet there are relationships that survive, couples that become closer and people who fall in love, sometimes with uninfected partners.

The doctors do not tell the uninfected partner that the other has the virus.

Abstain from sexual activity or be in a long-term mutually monogamous relationship with an uninfected partner.

The uninfected partner in 2 of 12 sexually active couples who said they regularly used condoms became infected.

The questions included condom use, limiting the number of sexual partners and being faithful to one uninfected partner.

Practice sexual abstinence, or limit sexual contact to one uninfected partner.

Dr. Greene has given the treatment only once: to the uninfected steady sexual partner of an infected patient after a condom broke.

There are other related arguments: One is "self defense," in which an uninfected partner could demand condom use to protect against infection.