Any malicious agent doesn't have to take it from you directly, taking it from your relatives is enough.

I suppose. But once there's a bunch of stuff online that's linked to your DNA data, anyone who has your DNA data can correlate it all. And tie it to your true name.

Bottom line, I see no compelling upside to putting ones DNA data on the Internet.

The upside is getting potentially profound information about yourself, in a way that is inexpensive and convenient.

There are also significant benefits to biological research. Most genetic variation is rare, and the effect of each of these rare variants is small, but they add up. Having access to larger datasets will allow us to be able to better correlate those variants to diseases. 23andme is already doing this with Genentech: http://www.forbes.com/sites/matthewherper/2015/01/06/surpris....

I do get that.

But what if 23andme or Genentech starts selling people's data to health and life insurance firms? And maybe employers will want that data, just as they want credit reports etc.

There ought to be meaningful privacy protection, in my opinion.

GINA prohibits them from selling it to health insurance firms or employers.

Not life insurance firms, yet, though.

That's why I would like to send my DNA in anonymously; I don't want to link anything to my DNA data.

Even if you send it in anonymously, your DNA is so unique to you that by comparing it to other data you can infer at least the last name.

See for example http://www.ncbi.nlm.nih.gov/pubmed/23329047

That's a valid concern, actually, my last name is fairly rare, especially in the United States.

Pay with a burner credit card, throwaway account? Access via VPN / LiveCD if concerned?

23andme knows my DNA. They know my email, and possibly where I bought the kit.

They don't know who I am, I hope.

And, regardless, I suspect the de-anonymization will be either so haphazard or so thorough in the future that it's not a primary concern.