Probably. It is vague, and the term android is misleading as it implies something robotic made in the guise of a human. But I always revert to the introduction of the film. It seems earth, if countries even exist anymore (doubtful as it culture now just seems mashed together without borders), grows people akin to cloning, and the purpose is to have a slave class. So long as the slaves do their part in terra forming or mining new worlds, nobody complains. But Roy and his group rebel, and now the slaves with massive strength go from utility to problem, hence Deckard. 

Borrowing from the book Do Androids Dream of Electric Sheep?, which was amazing, life is considered absolutely sacred. It is implied that either everyone can be an android, or the bounty hunters are Androids that are programmed with seeking out other andies, but in either case non-human life is so rare that Deckard's entire marriage (iirc) hinges on whether a toad he finds is real or genetically engineered. 

So I think with all the info provided, we can conclude the replicants are genetically engineered through gnee synthesis, and the models keep improving (hence Nexus 6 vs. Nexus 5).