A method for in-ova fertilisation determination and gender determination on a closed egg. The aim is to specify a method for the in-ovo fertilisation determination and gender determination on a closed egg. This aim is achieved by a method in which a closed egg is positioned, candled and/or illuminated, next an image of the closed egg is recorded, then the captured data are evaluated and the position of the cardiovascular system located in the egg is calculated. A detection unit is adjusted via the calculated position of the cardiovascular system by means of a positioning unit and subsequently the blood is stimulated, then the blood-specific and blood-foreign absorption spectra are detected and selected, the fertilisation is ascertained and then the spectra containing blood-foreign information are compensated by a compensation method and the spectra are classified for sex determination.