I think shielding can be accomplished much more easily for either eggs and sperm OR frozen embryos (I prefer the gamete rather than an embryo, similar problem as a bunch of sleeping adults)
BRANDON-yeh, I think we will establish the reachable "outposts" for industry or simple colonization . Maybe, at a time when some %(c) can be attained, we will be able to get to Alpha Centauri or Proxima Cetauri . I think that space travel of a few years is still achievable by a colonization crew. BUT, that aint deep space travel.
Then, I agree, building vehicles in place and constructed in space makes much more economic sense to make sure that all the mass of the vehicle isn't wasted in merely getting up to some escape velocity.
I still feel, that for deep space travel, humans are merely an "end deposit". Stuff like instructions or new technology information can be "radioed" ahead of a spce ship to be either intercepted on route or waiting for the whole colony when it arrives. Such dqta and information will be travelling at (c) and the colony vehicle will be at a %(c).
Unless we think about these HUGE planetesimal sized space ships(Like the MOTHER SHIP in "Independence Day"), then sending people to either reproduce en route or be kept "asleep" for a thousand yeqrs is wholly impractical IMHO. The technology to protect and awaken these subjects will be an unknown until its tried(no matter how we do "Concept tests" back home we will probably never do a complete 1000 year freeze with subject)
I think that sending frozen "Gametes in Space" will eventually occur to us as an attainable, technologically solvable way to do deep space exploration.
The issue of NEOTONY (where the babies retain, until about 11 or12 anna, that "cutesy" juvenile developmental shape).
Ive looked at several populations where WORK is expected of their kids (like Amish and Mennonites), kids QUICKLY become miniature versions of their parents at 5 or so.
Wed need to futz with the genetics a bit, but I still don't see anything better than this