A novel initiator, naturally occurring in soy, has been developed for a direct synthesis of aliphatic star-shaped homo- and copolyesters. The synthesis is based on one of several known isoflavones, genistein, which has been employed as an initiator of homopolymerization of poly(l-Lactide) or co-initiator of copolymerization of epsilon-caprolactone and l-Lactide with Sn(Oct)(2) as a catalyst. The non-toxic chemicals used allow for an inexpensive and safe for human body facile synthesis of biocompatible functionalized polymers suitable for medical and pharmaceutical applications. The obtained polymers were characterized by H-1, C-13 NMR, FT-IR, SEC-MALLS and MALDI-TOF MS analysis.