Embryos are cultured in an incubator which simulates the conditions inside the uterus by maintaining heat, humidity and pH. Embryoscopes are cameras which monitor the embryo’s development with a camera placed in the incubator. Following the embryo as it develops provides additional information to assist in selecting the best embryo for transfer. Time lapse photography of the developing embryo gives the ability to view more than 5,000 images over the same time period to observe and measure more closely each stage of division and growth. Determining delays in development at defined points in an embryo’s growth indicates an abnormal embryo. An experienced embryologist who monitors the embryos’ growth at several stages during the culture can also be equally effective at detecting abnormal embryo development. The advantages to time lapse photography of embryo growth are that clinicians and embryologists can evaluate and select embryos without taking the embryos out of the incubator. The disadvantages are the repeated light exposure of embryos, the possible toxic effects of electronic equipment and their silicone circuits in the hot and humid incubators.