Despite the fact that bisexual organisms have both male and female cells, they often cross-fertilize

Despite the fact that bisexual organisms have both male and female cells, they often cross-fertilize rather than self-fertilize. Explain why.

Self-fertilization is a bad idea for an individual as it does not bring diversity. In addition to the lack of new alleles of genes that would be useful for adapting to changing environmental conditions, there is a risk of manifestation of harmful recessive mutations in the phenotype, which will converge into a “nasty couple”. Cross fertilization provides both “new blood flow” and reduces the chance of such “couples” reuniting.