Board Thread:Theories and Speculation/@comment-25025726-20161107172956/@comment-24901923-20161130011316

While both Asuma and Indra apparently only reincarnate as males, it should be possible to conduct some genetic tinkering to make female versions of their genomes, which can be used to create female clones or gametes for test tube babies. Being the closest to the Sage of Six Path's chakra type, the combination of their genetics should result in replicating said chakra, in the same way Madara infused himself with Hashirama's cells and waited for them to spread through his body and achieve critical mass to blend their chakras to the point of awakening the Rinnegan. The reincarnations having children with members of the descendants of their counterparts might also work, come to think of it.