Male and female fertility were evaluated through the number of inseminations to conception, using a sequential threshold model. Male fertility was considered as a time-dependent effect allowing for different service bulls in each insemination. Posterior estimates for service sire variance and female fertility genetic variance were 0.02 and 0.04, respectively. Posterior mean for female fertility heritability, through liability to number of inseminations to conception, was 0.03. The correlation between male and female fertility was not significant. The sequential threshold model allowed for a simultaneous analysis of male and female fertility, including time-dependent covariates, as well as censored records. Hence, it is possible to consider both male and female fertility in the genetic evaluations. Thus, complete data and fertility estimates are provide to both farmers and artificial insemination studs. These estimates consider all information available and all possible factors affecting to male and female fertility.