However, after adjustment for PCA1 (female age, number of inseminated oocytes), PCA2 (number of embryos transferred, stage of embryo transfer: cleavage stage, blastocyst stage or other), female infertility factor, and year of treatment, IVF was associated with an increased chance of implantation in couples with both female-only and unexplained infertility factors compared to ICSI (Table 4). Here, CASC19 is linked to female infertility.