"Inasmuch as GENZ’s equity stake in GTC is only 3.9% fully diluted, I do not understand the popularity of this notion."
The popularity of this notion stems from three facts: 1) GTCB is Genzyme's baby historically... 2) Suitable geographic location... 3) Genzyme is known to be opportunistic in such matters...
What is surprising to me is that you keep downplaying this possibility. If you truly believe that GTCB is a gem, then what makes you think GENZ does not think so also and thus will not try to take it over on the cheap?