The method comprises irradiating said sperm cells with non-coherent red light, the irradiation with non-coherent red light being performed in a discontinuous manner according to a pattern including at least one sequence of two irradiation periods of specific durations which are separated by an intermediate period of darkness of a specific duration, wherein the sperm cells are diluted in a diluent with cryo-preservatives solutes and are included in said container in a frozen state, and said discontinuous pattern comprise a duration between 3 and 15 minutes.
