Copied from my post to a similar question here:
Rabbi Daniel Friedman, in an article entitle Pareve Meat (pp. 93-105), wrote a halachic analysis of this topic for the RJJ Journal of Halacha and Contemporary Society some years ago (Number LIII from Pesach 5767, Spring 2007). His analysis points to 3 possible conclusions:
- Not Kosher
- Kosher - Meat
- Kosher - Pareve
Each of these successive conclusions requires an additional level of complication and dependency regarding the Halachic analysis and a willingness to rule to the lenient side of Machloket. Issues involved which he cites include: Chatzei Shiur, ChaNaN (Chaticha Naaseit Neveilah), Ein Mivatalin Issur L'Chatchila, Davar HaMaamid, and Marit Ayin.
I'll conclude by quoting his conclusion:
Pareve "meat" would have to be grown in a medium or culture, which one cannot automatically assume would be kosher. Consequently, the entire process would require kashruth certification. It is unclear whether kashruth authorities would eventually determine the finished product to be fleishig or pareve. However, even if it is considered pareve, one must be aware of potential marit ayin issues, at least until the product becomes widespread. MOre to the point, it is highly questionable if any reputable kashruth organization would even be willing to provide hasgacha for such a product, inasmuch as the entire product is based on numberous heterim.