“Baby Mama” exceeded expectations and opened at No. 1 with a healthy $18.3 million versus $14.6 million for “Harold and Kumar Escape from Guantanamo Bay” (which reportedly cost $12 million) in second place. Former skewed 68 percent female, while the latter skewed 65 percent male. The sophomore sessions of “Forbidden Kingdom” and “Forgetting Sarah Marshall” were in a dead head for third and, as expected, “Deception” tanked with $2.2 million in 10th place. On the brink of Hollywood’s summer session, biz was up 17 per cent over the same weekend a year ago.