Measures on gay rights and child safety are among the top state laws taking effect at the start of 2013, along with perennial efforts to restrict abortion and illegal immigration.
In many states, new laws take effect on Jan. 1, while in others they do so 90 days after a governor's signature.
Voter-approved laws allowing same-sex couples to marry take effect in Maryland in January and in Maine on Saturday. California also approved a law exempting clergy members opposed to gay marriage from performing same-sex marriage ceremonies.
In California, a first-of-its-kind law bans a form of psychotherapy aimed at making gay teenagers straight but is on hold during a court challenge. The law would ban what is known as reparative or conversion therapy for minors; such therapies are widely discredited by medical professionals.
A number of laws seek to protect children from bullying and abuse.
Pennsylvania school employees in contact with children, who already must report suspected abuse, must now be trained to recognize the warning signs, their legal obligations and what are considered appropriate relationships with children.
California coaches and administrators in K-12 schools, as well as higher education employees who have regular contact with children, will be required to report suspected child sexual abuse. Oregon will require schools to adopt a policy on teen dating violence.
In Florida, the Safe Harbor Act includes provisions that require police to turn over to the Department of Children and Families any children who are alleged to be sexually exploited for assessment and possible shelter.
States continue to wrestle with illegal immigration. Pennsylvania will include a requirement that contractors on public works projects make sure through the federal E-Verify system that their employees are legal U.S. residents, while a Montana ballot measure taking effect denies state services to illegal immigrants.
Also in Montana, voters overwhelmingly passed a measure requiring parental notification for minors' abortions, while in Georgia a new law will prohibit doctors from performing an abortion 20 weeks after an egg is fertilized unless a pregnancy is determined to be medically futile, meaning it would result in the birth of a child unlikely to survive because of a serious defect. Georgia became the seventh state in the country to approve the so-called fetal pain act.
New Hampshire enacts a ban on a type of late-term abortion sometimes called "partial birth abortion" after lawmakers overrode Gov. John Lynch's veto.