Despite a daily regimen of birth control pills, Merah the orangutan is pregnant. And St. Louis Zoo officials are uncertain who the father is.

"Needless to say, we have a lot of unanswered questions," primate curator Ingrid Porton said. "It's a little embarrassing, I have to admit." Diligent about trying to prevent overcrowding and inbreeding, zookeepers have been giving 35-year-old Merah a daily birth control pill mixed into yogurt and honey. Porton suspects the mixture either spilled or was swiped by her eight-year-old son Sugi.

The how is less important than the who, however. Scientists hope the father is 40-year-old Junior, a previous mate with great genes. They concede it could be Sugi, Merah and Junior's son. Merah has had liaisons with both.