hamg now, attorney general eric holder says president obama has ordered the justice department to stop defending the constitutionality of the measure which defines marriage as only between a man and a woman. holder says mr. obama concluded that given a number of factors, including a documented history of discrimination, classifications based on sexual orientation should be subject to a higher standard of scrutiny. in new zealand, incredible rescues of around 30 people today in the earthquake devastated city of christchurch. hundreds are still missing, at least 75 people were killed when the quake struck new zealand's second biggest city yesterday. president obama is condemning the violence in libya and will make a public statement on the crisis today or tomorrow. meantime, the revolt against libyan leader moammar gadhafi appears to be growing. it's a question many of us ask and many of us seek to answer. do cell phones cause health problems? a new study evaluated the possible effects of cell phone exposure on the human brain. cnn senior medical correspondent