Watching the remarkable Xeni Jardin tweet her mammogram and cancer diagnosis, then blog eloquently about it, then crowdsource opening up her own MRI data makes me ask: Why are we so secretive about sickness and health? And what do we lose because we are?

The answers to the first questions are fairly obvious. First, we keep our sicknesses secret, we say, because we fear we could lose insurance. Except insurance companies force us to reveal our medical histories anyway. And let’s hope that Obamacare — may it survive the Supreme Court — succeeds in outlawing the denial of health coverage due to preexisting conditions. Next, we fear that we could lose jobs. Except in cases where a condition would affect job safety, shouldn’t employers be told that they cannot discriminate on the basis of health? Whether or not society chooses to address these issues through legislation, my point is that it’s possible to do so.

The other reason we keep sickness secret — the bigger reason — is stigma. We don’t want people to know we’re ill. But in this day and age, why should anyone be ashamed of being sick? To be clear, I am not saying that anyone should ever be forced to reveal health information. But why should our norms, stigmas, and economic considerations force us not to reveal it?

Imagine if we didn’t feel compelled to hide our illnesses. Imagine if we could be open about our health. What good could come of that?

We could learn more about correlations, which could yield information about causation and even cures. Given large data sets, we could find out that people who get a disease share common behaviors or characteristics. We might gain the opportunity to discover an environmental cause to a local outbreak of, say, breast cancer, enabling a community to fix the condition and prevent more cases.

Of course, I want to emphasize the conditional: correlation *could* help. One data point is never meaningful: That I’ve contracted one heart condition and two cancers since being at the World Trade Center on 9/11 is meaningless — unless there are many others in the same boat, and even then, one mustn’t jump to conclusions about causation. Still, more data is always better than less.

With openness about health, we could do a better job connecting people who share conditions to get information and support and each other. I am on the board of Learning Ally, formerly Recording for the Blind and Dyslexic, and at our last meeting, I was struck by the barriers that stigmas put in the way of young people getting the organization’s help. I heard how getting our software on iPods has helped more kids use the service because they no longer have to carry around a special device that marks them as different — stigma. I heard a mother say that school officials warned her that her child would be labeled — stigma — if she got him appropriate services, but she said she’d eagerly embrace the label if it got her son the help he needed.

On my blog, I’ve been in a debate about the recommendation by a government panel that men shouldn’t be given the blood test for prostate cancer anymore because, statistically, it hasn’t been shown to save lives. That’s because medical science can’t yet distinguish between fast- and slow-growing prostate cancer. I say men should get the test. I say we should be talking openly about our prostates as women have fought to talk about breast cancer. More information and communication is always better than less.

The real question is what men choose to do when they find out — through a biopsy following the blood test — that they have cancer. Perhaps more men should choose what the doctors call watchful waiting over surgery. But, you see, the problem is that we don’t have *enough* data to make a good decision. I want to know, based on the largest possible population, how long it took prostate cancer to spread after it was found. Then I could decide how long to watch and wait. But I don’t have that information. So I chose to get the cancer out of me. I could make that choice only because I had the test. I had my own data. If I had the data of millions more men, I could make wiser decisions.

How could get get more data?

Step one is to encourage men to talk about their prostates — and, yes, sorry, their penises — so we disarm the stigma about it and get more men to be aware and get tested and share their experience.

Step two is to create the means to open up and share as much health information as possible so researchers, doctors, and hackers can dig into it and find correlations and patterns and questions worth pursuing, perhaps leading to answers.

When I talk about the principles of an open society in Public Parts, this is what I mean. Rather than reflexively declaring that sharing information about ourselves — our bodies as well as our thoughts and actions — is dangerous, we must stand back and ask what benefit could come from such data, now that we have better technological means to open it up, gather it, and analyze it.

Only then can we balance the benefits and risks and decide, as a society, how open we want to be, how open we should and need to be — and why. That is the kind of discussion about privacy and our changing norms I’d like to hear. Let’s not just talk about what can go wrong now but also what could go right.

: LATER: Some added links:
* Larry Smarr quantifying his own health.
* On being a medical data donor.
* Give us access to our own health data, online.