The Immigrant Legal Resource Center has published an analysis of Matter of Guevara Alfaro, 25 I. & N. Dec. 417 (BIA 2011) (California conviction of sexual intercourse with a minor (statutory rape), in violation of Penal Code 261.5(d), does not categorically constitute a crime involving moral turpitude):

Because the Ninth Circuits earlier decision interpreting Californias sexual intercourse with a minor offense used the traditional categorical approach rather than the Silva-Trevio approach, the Board concluded that the earlier Ninth Circuit decision is not binding. Matter of Guevara Alfaro, 25 I&N Dec. at 421. Instead, the Board h[e]ld that the Attorney Generals substantive ruling in Silva-Trevino is binding in this case and must be applied in lieu of Quintero-Salazar to the extent that the two cases conflict. Matter of Guevara Alfaro, 25 I&N Dec. at 421 (citing Natl Cable & Telecomms. Assn v. Brand X Internet Servs., 545 U.S. 967, 980-82 (2005)).

Despite refusing to follow the Ninth Circuits earlier decision, the Board reached the same result regarding the first prong of Silva-Trevio. The California statute, it noted, does not require a perpetrator to have engaged in intentional sexual contact with someone he or she knew or should have known to be a child. Matter of Guevara Alfaro, 25 I&N Dec. at 424. As such, the statute fails the categorical approach that, as announced in Silva-Trevio, counsels that an offense is not a CIMT if there is a realistic probability that non-morally turpitudinous conduct would be criminally prosecuted under that statute. Matter of Guevara Alfaro, 25 I&N Dec. at 424. In California, the Board concluded, there is a realistic probability it could be applied to conduct that does not involve moral turpitude. Matter of Guevara Alfaro, 25 I&N Dec. at 424.

The Board then turned to Silva-Trevios second prong"the modified categorical approach in which the IJ can examine the record of conviction to determine whether moral turpitude is present. The BIA found that there are no documents in the record of conviction establishing that the respondent knew or should have known that his victim was a child. Matter of Guevara Alfaro, 25 I&N Dec. at 424.

Lastly, turning to Silva-Trevios third prong"which I describe as the anything goes prong because it allows an IJ to consider what seems to be a limitless array of evidence beyond the statute or record of conviction"the Board noted that the noncitizen did not deny knowledge of his victims age. Matter of Guevara Alfaro, 25 I&N Dec. at 424. The IJ, however, did not make any findings regarding whether the noncitizen knew or should have known the victims age, therefore the Board remanded the case so that the IJ could make appropriate findings. Matter of Guevara Alfaro, 25 I&N Dec. at 424. The implication, of course, is that on remand this may prove to be a CIMT thanks to the anything goes prong.
Thanks to Kathy Brady, Immigrant Legal Resource Center.