The author of Allegheny County's ordinance that restricts where convicted sex offenders can live after they've been released from prison had the stated goal of protecting children. But it turns out that's not what the law says.

Its principal author, Councilman Vince Gastgeb of Bethel Park, now says the ordinance never was intended to apply to offenders who committed crimes against adults, only those who accosted children.

Too bad the law is not that narrowly confined. It defines sex offenders covered by the law as any adult who has been convicted of a crime that requires reporting under the state's Megan's Law. That covers not only child luring, sexual abuse of children and crimes against children, but also includes nearly all other sex crimes regardless of the victim's age.

The flawed county measure has even more problems than were apparent when it was enacted last year, and a federal lawsuit filed this week by the American Civil Liberties Union of Pennsylvania takes aim at them.

First, the suit says, the restriction that prevents sex offenders from living within 2,500 feet of a park, school, day care or community center has the practical result of preventing convicts from living just about everywhere in the county. It was filed on behalf of six offenders and says the county law violates their rights to housing; five already live in the county and a sixth is stuck in prison because acceptable housing cannot be found.

The local ordinance also interferes with the monitoring and rehabilitation services conducted by the state and county probation and parole boards under Megan's Law. That law, which took effect in 1996, requires anyone released from custody after conviction of a sex crime to report where they live to authorities; police then notify the neighbors.

The suit also says the county has not yet complied with a provision that says it will post on its Web site a map showing what areas are off limits.

The law had its genesis in Mt. Lebanon, where a group of families who live near Howe Elementary School got worried when they learned a convicted sex offender was living nearby. The argument went that it was too risky to allow any sex offenders to live near schools or other places where children gather.

Never mind that very few attacks on children are perpetrated by a stranger. Ninety-three percent of child sexual-abuse victims knew their abuser and 34 percent of them were relatives, according to U.S. Bureau of Justice Statistics.

And never mind that, rather than achieving the goal of protecting children, such residency restrictions further isolate offenders and force them to live far from the social services and employment opportunities that are likely to help them become productive citizens.

Now Allegheny County resources will be wasted defending a bad law that was slapped together based on fear and the unfounded caricature of a lurking stranger.