A family friend sent me a baby gift from India. It is a small necklace of carved ivory elephants and beads. Both the necklace and I are 72 years old. What is the ethical choice for the necklace? I would like to do something to benefit elephants, but no elephant protection organization has answered my letters. Nancy Polk, Conn.

As you know, the reason the international ivory trade has been banned is to reduce elephant poaching and maintain the populations of these cognitively sophisticated animals. Both are worthwhile aims. No market for ivory, no incentive to hunt it.

That’s the logic, although how well the approach works is hotly debated. (One complication is that ivory is mainly smuggled to East Asia, where domestic trade is permitted in some countries. China, however, recently announced a new ban on trading and processing ivory, to take effect by the end of 2017.) Most African countries where elephants live have seen significant losses in elephant populations in the past two decades. There are exceptions. Namibia has set up communal conservancies, devolving management to local communities and allowing limited hunting; the government says its elephant population has been increasing. The problem is complex, and the solutions may have to be, too.

The circulation of antique ivory like yours doesn’t threaten modern elephants, of course. But there is concern that allowing it might, because people would pretend that new ivory was antique to get around the ban. That’s one reason that wearing even antique ivory jewelry offends some people. And it’s true that you can’t tell at a glance whether the jewelry was made of old ivory or new or, for that matter, faux ivory made from Tagua palm kernels, cow bones or resin. But you could say the same about piano keyboards. Old pieces of jewelry — and old musical instruments — shouldn’t be shunned because they were made of ivory.

So your coming into possession of this ivory necklace doesn’t entail your doing anything in particular. Commendably, though, thinking about the ivory has made you think about what you can do for the elephants alive today. It would be a fine thing to support a reputable organization that contributes to the welfare of the elephant population. But do your research. Just as you can’t tell the origin of ivory at a glance, you can’t tell at a glance whether one of the hundreds of organizations that claim to be protecting elephants is really doing effective work.

While planning a vacation, I decided that I would hire a local student to house-sit and dog-sit. My husband, who teaches at a local university, said he would get one of his students to do it free. When I brought up the possibility that the student could feel coerced, he said it would be a former student. My husband thinks that because he house-sat and cat-sat free for a professor in college, it’s O.K. to ask this of his students. I think that even if it was “O.K.” then, it isn’t now. There’s always a power differential between a faculty member and a student, and the faculty member should go out of his way to avoid any abuse of power. What do you think? Name Withheld

I’m with you. While someone who studied with you is entitled to do you favors, it isn’t right to ask them to do an unpaid job on that basis. Former students may be in need of recommendations and the like from former professors; there are forms of exploitation that fall well short of coercion.