<p>Disclosed is a means for improving fertility based on human blastocyst transfer. The means includes a fertility agent in the blastocyst transfer comprising a supernatant of a culture obtained by cultivation of human embryo in a culture until developing into a blastocyst. Also disclosed are a method for producing the agent and a method for increasing fertility in a human, comprising culturing a human embryo in a medium until it develops into a blastocyst, injecting a composition containing a supernatant of the culture into the uterine cavity of a human patient who is going to undergo blastocyst transfer, and transferring the blastocyst to the patient.</p>
