>>9013870
There are two stigmas against Pureblood pairings: Ardat-Yakshi and the belief that each Pureblood pairing is a squandered opportunity to intermarry with other species.
The chance a Pureblood pairing will produce an Ardat-Yakshi is very low. Asari reproduced with each other before meeting other species. They still do. Liara is a Pureblood asari. Samara's children are all Purebloods.
>>9014058
A better comparison would be comparing Ardat-Yakshi to lethal genetic disorders in humans. Humans didn't stop reproducing just because they might produce offspring with lethal alleles. Asari didn't stop reproducing just because they might produce Ardat-Yakshi. They created a social stigma about Pureblood pairings instead.
>>9014072
Asari are related to the manal, a Thessian organism called the "asari chimpanzee." This means the asari and the manal share a common ancestor. Asari are native Thessian life.