Odd Reasoning:

In re Bobrowich, 2003 WL 230701 (N.Y. City Civ. Ct.), was one of the cases that barred a man from changing "an obvious male name" (Stephen) to "a name that is commonly used as a shortened version of the female name" (Steffi), at least absent evidence of transvestitism, transsexuality, or maleness of the name in "some other culture."

But there's more, because Stephen Michael Bobrowich wanted his name changed not just to Steffi Michael Bobrowich, but to Steffi Owned Slave, because "I feel that I have been treated as a slave my whole life, being paid minimum and treat as dirt I wish to show that I am." No dice, the court said, giving a longish discussion of the history of abolition of slavery in New York, and concluding:

Owing to the fact that slavery is illegal in the State of New York, the Court cannot change the name of the petitioner to something that reflects this illegal status and is therefore objectionable. As stated above, since the Court is being asked to issue an order changing the petitioner's name, it could be interpreted that the Court is endorsing this illegal status and reprehensible condition. In Application of Thompson, 82 Misc.2d 460, 369 N.Y.S.2d 278 (Civ Ct. N.Y. Co.1975) the court refused to allow the petitioner to assume the name "Chief Piankhi Ankinbaloye," since by approving the name "chief" the court would be bestowing an apparent title of authority on the petitioner.

Now this just makes no sense. Having a last name of "Slave" doesn't reflect any illegal status, just as having the last name of "Painter" doesn't reflect one's status as a painter.

Nor does a court's approval of the name "Steffi Owned Slave" bestow an apparent title of authority. I'm not sure that even "Chief" would have this effect, but at least there are chiefs (presumably American Indian chiefs or people who hold this title in foreign countries) in the U.S., so someone could think "Chief" is indeed a real title. Everyone knows slavery is illegal in the U.S.; no-one would see this as "an apparent title" "bestow[ed]" by the government. Plus when slavery was legal, it in any event wasn't marked with "Slave" being used together with one's name.

Now I sympathize with the court's desire to play no part in what it sees as an offensive exercise, or one that's likely to cause needless friction and offense to the public. It may well be that some such limitations on official name changes are indeed proper. But the court's ostensible reasoning, it seems to me, is a pretty weak support for its conclusion.

Thanks to Timothy Sandefur for the pointer.