For the record, only the 1st edition of the Pocket Guide to the Empire mentions that Altmer kill 9 out of 10 children...this Guide to the Empire is published at the request of Tiber Septim himself. The 3rd edition was published at the request of Uriel VII (Emperor at the start of the Oblivion Crisis) and no mention was made of an Altmer eugenics program.
The first guide is heavily biased, written with a fair amount of propoganda, particularly anti-mer, so I hold this "fact" to not really be proven.
However it is written that Altmer and Dunmer do not reproduce very quickly, in spite of their longer life spans.