Will Saletan of Slate gave this new blog a very gracious shout-out yesterday - many thanks. He also replied to my earlier post taking Will to task a bit about “designer dogs.” I’d suggested that dog breeding is a bad analogy to bring home the problems of genetic trait selection in humans, because the former is so familiar and non-threatening. Will replied that he used a familiar example on purpose, and wondered what other analogies might work better.

To answer that, it helps to think a bit about what’s troubling in the first place about genetic trait selection for people. Breeding dogs with 25-year-old frozen sperm from a former champion doesn’t quite get at what disturbs me about human trait selection. Some people already have done a version of the dog trick with the now-defunct “Nobel Prize sperm bank” - the moral equivalent of breeding a former dog show champion. The Nobel bank was creepy, but it remained something of a fringe practice, even though it offered an easy route to instant eugenics.

One reason it stayed a fringe phenomenon may have been the lack of control prospective parents had over the outcome. You couldn’t really be sure your Nobel offspring would be an Einstein, and the child might lack good looks and social graces altogether. The Nobel bank may have boosted the odds that your child would have the desired traits, but it still relied on old-fashioned, largely unsupervised egg-sperm unions.

Pre-implantation screening of traits gets you more control, and that kind of control is what worries me most. Babies should be a little surprising - as in, “Whoa, red hair! Where did that come from? Loves art - who knew?” Having a child has always meant opening yourself up to something new and unpredictable. But meticulously screening out the traits you don’t want would bring a level of control that the Nobel bank never offered.

Maybe gambling is a better analogy for the problem than designer dogs. Reproduction the old way amounted to an honest roll of the dice. Now the dice could be loaded to prevent novelty.

That idea doesn’t make me sick - sorry, Will - but it does violate my parental sense of fair play. And if children lose their power to surprise, it will drain a bit of wonder from the world.

A confession: as much as I like the idea of bloggingheads.tv, I often find the thing itself unwatchable. Too much chit-chat, not enough substance. One longs for an irritating Chris Matthews-like presence, badgering everyone to stay on topic.

But this is a worthwhile exchange between two very good science bloggers - biology blogger Carl Zimmer and astronomy blogger Phil Plait. The question is whether science blogs might do a better job of covering science than traditional media sources, which are constantly cutting back on many specialties, including science coverage. Plait in particular believes that the rise of blogs powered by real scientists offers something as good or better than the coverage from newspapers or CNN.

The idea has some appeal, and it’s one of the reasons why we started this site. In terms of sheer science knowledge, the researchers and physicians at this university would beat any news desk in the country. If we can unleash more of that expertise, it can benefit medical consumers and the broader conversation about science.

Yet I would hate to see newspapers fade as providers of reliable science coverage. Plait is right that many scientists are excellent writers, and blogs like his can cover some stories more effectively than traditional media (his recent real-time coverage of the “Texas fireball” - probably a meteor - is a great example). But science stories benefit immeasurably from good editors, along with teams of photographers and graphic artists who can pull together complicated information into a package that any reader can digest in a few minutes (see Zimmer’s engrossing Times package from last November on changing ideas about the role of genes). Scientists excel at producing knowledge, but only some can make good sense of their field for a general audience. Newspapers ought to help fill that need.

Of course, fewer and fewer papers or networks have the resources to do that. It’s a problem not just for science journalism, but for science in general.