During which phase of meiosis is the chromosome number reduced?

The chromosome number is reduced during the telophase II stage of meiosis. This last of eight stages of meiosis results in the formation of four daughter cells.

During the previous seven stages, a single cell replicates into two cells with an equal number of paired chromosomes. In telophase II, the paired chromosomes move apart without replicating, creating two mirrored half-sets of chromosomes. Simultaneously, nuclei form at two opposite sides of each cell. Finally, cytokinesis, or cell division, occurs again in each cell. A total of four cells with a half-set of chromosomes each are created, ready to be transformed into egg or sperm cells.