An important result of meiosis is that:

Analyze the options: The first option, 'genetically identical cells are produced,' is incorrect because meiosis results in genetically diverse cells due to crossing over and independent assortment. The second option, 'the chromosome number is reduced by half in gametes,' aligns with the purpose of meiosis. The third option, 'sister chromatids remain attached in all daughter cells,' is incorrect because sister chromatids are separated during Meiosis II. The fourth option, 'DNA replication occurs twice,' is incorrect because DNA replication occurs only once, during the S phase of interphase, before meiosis begins.

Focus on the correct answer: The chromosome number is reduced by half in gametes. This reduction ensures that when two gametes fuse during fertilization, the resulting zygote has the correct diploid chromosome number.