Very expensive to produce with current technology
Requires enormous capital investment for Research & Development
Unnatural
People might be reluctant to switch over from normal meat
Limited (for the near future) to ground meat (it’s more difficult to produce a steak or drumstick)
Subject to media criticism (see Stephen Colbert’s report on Shmeat, “Combination Shit and Meat”: Says Stephen of prototype in-vitro meat, “That looks like an egg yolk made of blood.”)
Possible unknown health consequences? (Will need to be carefully tested in FDA clinical trials.)