The WomanCare Centers of Florida Birth Control Center, 1622 N. Federal Highway, sustained extensive smoke and water damage during the 11:09 p.m. blaze.
Lake Worth police and fire departments, State Fire Marshal's Office and the federal Bureau of Alcohol, Tobacco, Firearms and Explosives are investigating.
The blaze may have been caused by a firebomb, police said.
The center's owner couldn't be identified.
Anti-abortion activists gather at the center every week for peaceful prayer sessions, said Susan Pine, president of Face Life, a local anti-abortion outreach group, who organized two vigils in front of the center shortly after it opened about a year ago.
Pine said no one in her group was behind the fire.
"Our activists are nonviolent, churchgoing people who would have no thoughts of doing something like that," Pine said. "It's not what pro-lifer people believe in."
The same philosophy is shared by Palm Beach County Right to Life, said Rich Giesman, an activist with the group whose members regularly pray across from a West Palm Beach abortion clinic.
"For us, it's about conversion. It's not about doing damage to property," he said.
The incident was reported to the National Abortion Federation, an association of abortion providers from the United States and Canada that works to keep abortions safe, legal and accessible. The Lake Worth clinic was not a member, according to the federation.
The federation cited as of January one incident of arson against an abortion clinic in the United States and Canada. There were three incidents in 2003, one in 2002 and two in 2001. Since 1982, there have been 169 arsons and bombings of abortion clinics, according to Bureau of Alcohol, Tobacco. Seventy-seven of these incidents have been solved.
In May 2003, an arson fire and vandalism damaged a Tamarac abortion clinic.
Just past midnight, a fire was started at Dr. Michael Benjamin's office when someone poured flammable liquid on the door and through the mail slot. The small fire burned itself out but caused smoke damage inside. Police also found red paint blotted out the doctor's name on two building directories and defaced parking spaces.
Police suspected the attack was the work of political or religious extremists.
Anyone with information about the Lake Worth fire is asked to call Lake Worth Police Department at 561-586-1611.
