WASHINGTON — Democratic presidential nominee Barack Obama said yesterday that he was probably too flip when he said it was "above my pay grade" to answer a question about when is a baby entitled to human rights.

Obama gave his answer last month at a televised religious forum sponsored by minister Rick Warren at his megachurch in Orange County, Calif.

Asked yesterday whether the "above my pay grade" answer was too flip, Obama said: "Probably. ... What I intended to say is that, as a Christian, I have a lot of humility about understanding when does the soul enter into ... It's a pretty tough question.

"And so, all I meant to communicate was that I don't presume to be able to answer these kinds of theological questions."

In a separate interview, Obama's running mate, Sen. Joe Biden, a Roman Catholic, answered a similar question by saying that he accepts his church's teachings that life begins at conception, but that the issue is personal.

He said it wouldn't be right to impose his views on others.

Meanwhile, Obama plans to lunch with former President Clinton on Thursday in what will be their first extended face-to-face meeting since the primary season.

Obama will be in New York that morning for a memorial ceremony at ground zero, where he will appear with Republican presidential rival Sen. John McCain to commemorate the seventh anniversary of the Sept. 11 attacks.

Relations between the former president and Obama have been somewhat strained following the primary season, in which Sen. Hillary Rodham Clinton also sought the presidential nomination.

During that time, Bill Clinton repeatedly questioned whether Obama had enough experience to be president compared with his wife.

During his speech at the Democratic National Convention last month, Bill Clinton expressed strong support for Obama's candidacy and made clear he will do what he can to get him elected.