#$%^&*AU2018203247A120180531.pdf#####ABSTRACT OF THE DISCLOSURE The sex of embryos in eggs is influenced or controlled through the application of light having selected wavelengths in order to promote the development of embryos of a selected sex. An incubating device is provided having an interior cavity that can be sealed from an outside, and having a plurality of lighting elements disposed on each of a plurality of trays disposed in the interior cavity. Eggs are disposed on the trays, and pre-determined environmental conditions are applied to the interior cavity to promote hatching of the eggs. Concurrently with the application of the environmental conditions, the eggs are irradiated according to pre-determined lighting conditions. The lighting conditions include applying light having wavelengths substantially concentrated in selected ranges, such as light wavelengths within the 390-419 nm, 410-450 nm, 420-450 nm, 450-495 nm, or other narrow range.