PALO ALTO, Calif. My meeting the other day with a hot new San Francisco startup began routinely enough. Ikea-furnished office full of Macs, shaggy company dog, high-end iced coffee -- check. Then former PayPal CEO Max Levchin walked in and started talking about cervical mucus. And about sexual positions, and whether certain configurations work best for conception. "Does female orgasm make a difference?" asked Mike Huang, one of the startup's co-founders. It was around the time that Levchin declared his intention to "help crowdfund a lot of babies" that I worried I'd been sucked into an Onion parody of TechCrunch.
In 2010, Levchin sold Slide, the social-media company he founded, to Google for more than $200 million. He left Google in 2011, and now he's assembled a team of software engineers and designers at a tech incubator called HVF, which stands for "Hard, Valuable, Fun." The incubator's latest incubation is Glow, a fertility-tracking app that launches in the iOS App Store on Thursday.
There are lots of apps and sites that do what Glow does, plus several products that are much more precise at predicting fertility than calendar-based tracking. (My wife and I found these pee-on ovulation tests messy and hard to read, but also cheap and effective.) But Glow isn't a mere ovulation calendar. Instead it's something more ambitious and, depending on your views about your personal data, it's creepier.
It's a data tracker. Rather than just letting you know when you should try to have a baby, Glow asks users to routinely enter extremely detailed information about their health and sex lives. The app is the first instance of a dream Levchin has been talking up for the past few months -- to improve health care through the large-scale collection and analysis of data.
But I'm skeptical that Glow can do that, for one simple reason: It is astonishingly intrusive, asking you more about your life than you'd feel comfortable telling even a doctor. For most people, though, the app won't provide much immediate benefit in return for the data they divulge. Glow is inspired by the rise of the much-hyped "quantified self" movement. These tech-loving, early adopter types argue that as we all begin to collect our health information through apps and small wireless sensors, we'll all gain a greater understanding about illnesses, sleep cycles and even emotional well-being. Yet more than showing off the possibilities for how data might change medicine, Glow underscores all the hurdles to making large-scale tracking a mainstream pursuit -- and shows why, for the foreseeable future, quantifying yourself seems destined to remain a fad.
Every day, Glow wants to know as much about you as you have time to answer, including your morning body temperature; the texture and "wetness" of your cervical mucus; whether you had sex and, if so, the position (the choices are "On bottom," "In front," "On top," and, helpfully, "Other"); if you are experiencing "emotional discomfort" (select green check mark or red X); your weight, if it's changed; and whether you're menstruating. The app also asks the male half of the couple questions about his nutrition and physical activity. And Glow isn't just for people who are trying to have -- or actively want to avoid having -- a baby. Ideally, Levchin would like every woman to use Glow, even those who haven't given any thought to having babies.
Why? Because data. Data, data, data, data, the vague and all-powerful buzzword at the core of Levchin's -- and quite a few other startups' -- ultimate goals. In the short run, the more information that Glow collects about women's menstrual cycles and sex lives, the more precisely it can predict when people should try to have a kid. With enough data, though, HVF hopes to make much larger predictions about people's health, nutrition, relationships and reproductive outcomes.
Hence our discussion about sexual positions and female orgasms. "Surely you have heard position matters, but is that true?" Huang says. "There's talk about it, but we don't know. With this, we'll know." That is, if the Glow team notices that women who chose "On top" end up getting pregnant more often than women who selected "On bottom," it will have answered a question for which medical science has no definitive proof. (I don't know what would happen if "Other" turned out to be the most effective position.) With enough data, Glow could even spot correlations that few in medicine might ever think to study. "Like if we find that men drinking 10 Mountain Dews a day is the surefire solution," Levchin jokes. Then he adds: "It would be awesome if we could be partly responsible for finding a cure for infertility."
OK, really? Could this really work? Critics of the quantified-self movement -- the writer Evgeny Morozov heads the pack -- say that folks like Levchin are helping to impose a nearly totalitarian, privacy-free future in which we'll all be forced to track our bodies all the time. In my multithousand-word debate with Morozov earlier this year, I took a more pragmatic view of health-tracking technologies: Devices like the Fitbit and Up can be helpful when they point out things about your life that you can improve -- for instance, that you should walk more. Often, though, I've found that these technologies provide few useful insights. I've tried out several sleep-tracking gadgets and found them useless. I already know I don't get enough sleep. Wearing a wristband is only making me feel worse about it.
Glow will face a similar problem. "We need you to enter the data not 100 percent of the time, but still relatively consistently," Levchin says. In beta tests with a few hundred users, HVF discovered that people who had already experienced some problem conceiving were more likely to engage with Glow. "When you move from a casual user into an obsessive user, we had no difficulty getting people to volunteer all kinds of information," Levchin says.
But the vast majority of people who try to have children face no trouble at all; they'll get pregnant without the app, sometimes without even meaning to. Levchin concedes that others who do consult the app will likely get pregnant after just a month or two. What immediate benefit do those people get for entering all the data Glow asks of them, especially when there are more conventional ways for them to determine their fertility? Little benefit, it seems. Levchin says that in Glow's beta tests, these early stage users were less willing to divulge all their data. That's a problem for Levchin's dreams of data-fueled insights. If a whole lot of women are getting pregnant using sexual position "on top," but they're not diligently entering in their data because they don't yet find the app useful -- after all, they're getting pregnant very quickly -- Glow's data will miss the effectiveness of that sex position. "The No. 1 challenge with this product will be compliance," Levchin says.
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So what's his solution? As Florence Williams wrote in Slate earlier this summer, Glow's most novel feature is a form of infertility insurance called Glow First. Users can contribute $50 a month to the plan; people who get pregnant forfeit their money, while those who don't conceive after 10 months will receive a portion of the money in the fund to pay for infertility treatments. Glow takes no cut of the fund. It also makes no guarantee about the eventual size of the fund. Levchin is contributing $1 million of his own money, though, and he hopes that the fund will grow large enough to pay for couples' in vitro fertilization, which can cost tens of thousands of dollars. The fund can also help with data collection -- people who are paying $50 a month for the service might be more committed to enter their data than those who are using it for free.
The problem with Glow First is that it suffers from obvious adverse selection. Most insurance plans don't cover infertility treatments, so when people who've been having trouble conceiving hear of a $50-a-month plan that will get them some financial help in 10 months, they're going to rush to sign up. Meanwhile people who aren't having trouble have little reason to pay -- especially if they find that the app asks too many questions. So I don't see how Glow First can sustain itself.
When I pressed Levchin on some of these questions, he didn't deny the challenge. Instead he looked to the future. Not long from now, he suggested, an app like Glow won't need to ask as many questions as it does. Instead it would automatically gather data through sensors that you attach to your body. A wireless thermometer that sticks on a woman's skin, for instance, could provide Glow with enough data to figure out when she's ovulating. If we connect them and analyze their data, sensors for weight, activity, and other physiological metrics would be able to suss out lots of other medical conditions, he says. For instance, congestive heart failure is often presaged by a sudden spike in weight over a period of a few days. If people were regularly stepping on intelligent bathroom scales, we might be able to spot heart failure before it's too late, saving lives and billions of dollars in emergency room visits.
Again, though, the trouble with this scenario is incentives. Why would people buy these scales if they're not prone to heart failure? Why would women who have no interest in conceiving attach wireless thermometers to their skin? Levchin says that at some point, such tracking devices will lead to such obvious improvements in health -- and savings in medical costs -- that insurance companies might require that we use them. This happens to be the exact scenario Morozov fears -- that by creating a market for these devices, quantified-selfers will make tracking devices requirements, not fads.
I'm not so scared. I think that before we get to a world where insurance firms mandate tracking devices, we'll need to see a lot of evidence that large-scale health-data tracking can be useful and isn't just a gimmick. Glow is one of the first apps on the market that will test that proposition. And from what I've seen of it, I think most people will be better off sticking to the pee sticks. Messy as they are, you can be sure they won't ask you to describe, exactly, what you mean by "Other."
• Manjoo is Slate's technology reporter and the author of "True Enough: Learning to Live in a Post-Fact Society." Twitter: fmanjoo