CAIRO — More than a week after Egypt’s 81-year-old President Hosni Mubarak underwent surgery in Germany, the Arab world’s most populous country is churning again with speculation over his condition.

But this time the rumors, which sent Egypt's stocks down on Sunday and Monday, underscore heightened uncertainty in Egypt over who will succeed Mr. Mubarak. Democracy advocates are pushing for the ability to elect a leader in a free and fair election, hoping to overturn a regime that has overseen human rights abuses and intimidated opposition parties such as the Muslim Brotherhood.

“Egypt is facing a serious and critical moment, and everybody feels it,” says Hassan Nafaa, a political scientist at Cairo University who has organized a campaign against hereditary succession in Egypt. “This will make it worse, certainly.

State media and the German hospital where Mubarak underwent his surgery have reported that the president is recovering well. But that has not stopped Egyptians from speculating about his possible demise.

Mubarak has ruled Egypt for nearly 30 years and said he would rule until his “last breath.” He is widely perceived to be grooming his son Gamal to take power - though many analysts predict that Mubarak may attempt another six-year term before passing the torch. But the energizing presence of newcomer Mohamed ElBaradei, the former head of the UN’s nuclear monitoring agency who returned to Egypt in February, is pressuring the government to enact reforms and Mr. ElBaradei is hinting that he might run for president. He is widely seen as more qualified than Gamal Mubarak, a businessman who heads the ruling party’s policy secretariat.

Prolonged absence? A lesson from Nigeria

Prof. Nafaa says people may ask more probing questions about the president's health if Mubarak doesn’t appear on TV by next week, but says it’s still too early to know what would happen in case of a prolonged absence. That’s a scenario that played out recently in Nigeria, where the president returned home last month after more than three months at a Saudi Arabian hospital. Nigeria’s parliament declared the vice president acting president in a controversial decision during the president’s absence.

Mubarak has no vice president; he temporarily delegated his power to Prime Minister Ahmed Nazif before his surgery. If he were declared medically incapable of being president, the constitution mandates that the speaker of parliament would become interim president and that elections should be arranged within two months.

Mubarak headed to Paris, Egyptian resort for rest

Mustapha Al-Sayyid, a political science professor at the American University in Cairo, said he had learned from sources he trusts but would not reveal that Mubarak will travel to Paris next week for a week of convalescence then rest in the Egyptian resort town of Sharm El Sheikh before returning to Cairo.

But even if Mubarak returns to Egypt in good health, the episode is still likely to affect next year’s election. If he runs on the ruling National Democratic Party (NDP) ticket, the opposition will use the surgery as proof he’s too uncertain a choice. If he doesn’t, it will put the NDP in a bind.

“If the president does not decide to be [the NDP’s] candidate, it will have to decide whether Gamal Mubarak would be its candidate, or it would have to look for somebody else capable of the challenge of facing a person like Mohamed ElBaradei,” says Sayyid. “It’s important for the NDP to demonstrate that it has experienced, capable candidates, and I don’t think these two qualities are met by Gamal Mubarak.”