Agartala, Tripura: Scientists have grown an entity that closely resembles an early human embryo, without using sperm, eggs or a womb. The Weizmann Institute of science /nature team say their "embryo model", made using stem cells, looks like a textbook example of a real 14-day-old embryo.It even released hormones that turned a pregnancy test positive in the lab. The ambition for embryo models is to provide an ethical way of understanding the earliest moments of our lives.