I’m delighted that Dan Klein is engaging my defense of designer babies.  Here’s my reply, point-by-point.  Dan’s in blockquotes, I’m not.

The idea that technology will enable designer babies fills me with
apprehension. My apprehension over designer babies would be great even
on two unrealistic assumptions: (1) That the government never got
involved in it (specifically, never made use of it or influenced the use
of it), and (2) That the technological development did not lead to
reductions in liberty, reductions prompted by results of the
development.

OK.

Designer babies would attenuate coherence with the past: One hundred
years hence, people would say, “When you watch him on the old videos, he
may not look like much, but back in the old times, Mike Tyson was
considered a pretty menacing fighter.” People in the new times would not
know our sense of standard. And they would have difficulty knowing it.
Everything preceding the break, from Achilles to Rafael Nadal, would be
foreign and unintelligible.

You could say exactly the same about all the economic growth that happened since 1900.  It has undeniably and dramatically “attenuated coherence with the past.”  I’m tempted to say “So what?,” but what I really think is, “Good riddance.”  The world’s improved beyond anything my great-grandparents could have imagined.  I hope my ancestors would have had the good sense and benevolence to be happy for me.  I’m happy for my super-descendents already.

People would lose a sense of historical coherence, a very important
dimension in human meaning. But even within their time, across arenas,
people would lose a sense of standard.

I’m a lifelong history buff.  The main thing I learn from history is that the past was awful, and the present far from satisfactory.  A future society of designer babies should be more able to appreciate this lesson because they’ll be beyond so many of our failures. 

In any case, most people currently have almost no sense of “historical coherence,” so they won’t be losing much. 

People would diversify in
extremes, to the point of regarding those in other arenas of activity
(the musicians, the athletes, the scholars, the thinkers) almost as
separate species, literally a specialized breed, and be little able and
little interested in trying to relate to them. “Am I supposed to
applaud?” “Am I supposed to try to remember his name?”

We’re already grateful for the amazing fruits of specialization that we already enjoy.  I see no reason not to embrace further specialization. 

Whatever sense of standard people did have, they would expect it to
dissolve quickly. So the breakdown in historical coherence would be in
relation to both the past and the future. Every generation would bring
drastic changes in standards, changes that were unforeseen and yet
unsurprising.

Again, this applies equally to rapid economic growth.  Think about the breakdown of “historical coherence” between Maoist communes in 1960 and modern China.  Good riddance.

I’ve used examples from sports, but I think the troubles pretty well
carry over to broader areas of life, including even wisdom and virtue. A
main point of Polanyi’s book The Study of Man is that
reverence, that necessary instrument for perceiving greatness, is
especially applicable in the pursuit of wisdom and virtue. Those, too,
might have some genetic basis. But whereas we would still know which
ball players hit the most home runs, here we might have even greater
difficulty recognizing the standouts. And inasmuch as we did recognize
the standouts, or thought we did, we might regard them as we regard the
new home run champions: more as a specialized breed than as exemplars.
Would I ever have bothered to dwell in Michael Polanyi’s thought if I
knew he were a designer baby?

The Dan Klein I know would focus on the quality of Polanyi’s arguments, not his origin story.  That’s what we should all do.

Adam Smith held that all moral approval relates to a sympathy; the
sympathy ratifies or underwrites the approval. Suppose, on Smith’s
authority, that the principle is sound. It would be just as sound in a
world of designer babies. But in such a world, the sympathies themselves
would be terribly attenuated, and hence also the moral approvals
underwritten. I think our moral confusion would grow more confused; I
suspect that the result would be moral and spiritual life that is
shallower, not deeper.

Dan, do you really think parents are going to select against genes for sympathy?  That’s very hard to believe.  Kindness is one of the main things parents try to instill in their kids.  If anything, we should expect designer babies to feel more sympathy, not less.

Now, here are some reasons why the two assumptions are not realistic
(and why my apprehensions are greater still): If political disposition
in an individual has some genetic basis, then, just as governments got
involved in schooling, governments would likely get involved in
designing babies.

Possibly, but I’m not worried.  In Western societies, controlling reproductive choice is widely seen as totalitarian.  Who today does not recoil in the face of the Supreme Court’s notorious 1927 decision to allow mandatory sterilization?  I am however worried that Western societies will deprive individuals of the right to use reproductive technology as they see fit, preemptively killing off an promising source of human progress.

As for other
repercussions on liberty, consider these: (1) Designer babies would
devastate social coherence, connectedness, and personal meaning as
generated by voluntary, non-governmental affairs, and consequently, in
demanding them, people will look ever more to governmentalization;

I can imagine designer babies would lead to marginally worse outcomes along these lines.  But why on earth would you expect designer babies to “devastate” anything? 

Though to be honest, I hope Dan’s right.  In my view, existing levels of “social coherence” and “connectedness” are dangerously high, the cause of most of man’s inhumanity to man.  See Dan’s great work on “the people’s romance.” 

(2)
If designing your baby is expensive, “the rich get richer” and “level
the playing field” will be louder than ever.

The same goes for any high-cost novelty.  Fortunately, the market usually outmaneuvers populist bellyaching long enough to turn novel luxuries into affordable conveniences.

Liberalism brought rapid cultural change (see the first of the two trends I present in this 17-min video.)
I detect, especially in libertarians, a denial regarding the downside
of rapid change – and I mean a downside even apart from resultant
greater governmentalization.

But don’t get me wrong about libertarians; they are not unique in
letting their ideological commitments distort their interpretations and
judgments.

Count me a libertarian “denier.”  Downsides notwithstanding, technological and economic progress are great.  To even selectively rebut the massive presumption in favor of progress you need to point to something like Hiroshima in 1945, not intangible worries about historical coherence.