A girl born in Manila, Philippines to a struggling family was the person anointed as the 7-billionth born in the world by the charity, Plan International.

Danica May Camacho, born in a crowded public hospital under the light of photographers’ flashbulbs. She was welcomed into the world with a chocolate cake marked “7B Philippines” and a gift certificate for free shoes.

With millions of births – and deaths – happening around the world every day, it is impossible to pinpoint the exact arrival of this planet’s 7 billionth occupant, so the celebration surrounding Danica’s birth, which included speeches by officials, was more symbolic than anything else.

The UN declared today a day of celebration to mark the symbolic 7-billionth babies being born and there were a string of festivities worldwide.

Danica was the first, arriving at Manila’s Jose Fabella Memorial on Sunday. Doctors say that was close enough to count for a Monday birthday.

“She looks so lovely,” the mother, Camille Galura, whispered as she cradled the 2.5-kilo (5.5-pound) baby, who was born about a month premature.

The baby was the second for Galura and her partner, Florante Camacho, a driver who supports the family on a tiny salary driving a ‘jeepney,’ the ubiquitous four-wheel drive vehicles used by many poor and working-class Filipinos.

Dr. Eric Tayag of the Philippines’ Department of Health said later that the birth came with a warning.

“Seven billion is a number we should think about deeply,” he said.

“We should really focus on the question of whether there will be food, clean water, shelter, education and a decent life for every child,” he said. “If the answer is ‘no,’ it would be better for people to look at easing this population explosion.”

In the Philippines, the subject of population is inextricably linked to birth control, with the government backing a program that includes artificial birth control. However, the Roman Catholic church, which is a powerful force in the Philippines, vehemently opposes contraception.

The world achieved its first population milestone of one billion in 1804, and a century later, in 1927, it hit 2 billion. However, in the 20th century, things begin to escalate. There were 3 billion by 1959; 4 billion by 1974; 5 billion in 1987, and by 1998, the world’s population stood at 6 billion.

UN demographers estimate the world’s population to reach 8 billion by 2025, and 10 billion by 2083.

However, not everyone is taking the UN’s estimations, seriously. According to some experts, the UN has jumped the gun.

The US Census Bureau says the most likely date the world population will reach seven billion is between March and April next year.

Sergei Scherbov of the Vienna Institute of Demography, meanwhile, says there is a 95% probability that the figure will be reached between January and July 2012.

Even the UN’s population estimates chief, Gerhard Heilig, says the UN recognises that its own figures come with a 1-2 per cent margin of error. Today’s population could actually be 56 million higher or lower than seven billion, Mr Heilig says.

“There is a window of uncertainty of at least six months before and six months after the 31 October for the world population to reach seven billion,” he told the BBC.

In any case, the celebrations roll on.

In Uttar Pradesh, India, which is the second most populous state in the world’s most populous country, officials appointed seven girls born Monday to symbolise the 7 billion.

India holds a skewed sex ratio among its population because of a deeply-held preference for sons. It is normal for female foetuses to be aborted. The country’s government is using today to mark that issue.

“It would be a fitting moment if the 7 billionth baby is a girl born in rural India,” said Dr Madhu Gupta, an Uttar Pradesh gynaecologist. “It would help in bringing the global focus back on girls, who are subject to inequality and bias.”

According to U.S. government estimates, India has 893 girls for every 1000 boys at birth, compared with 955 girls per 1000 boys in the United States.

On Monday, the chosen Indian babies were being born at the government-run Community Health Centre in the town of Mall, on the outskirts of the Uttar Pradesh capital of Lucknow.

Six babies were born from midnight to 8am Monday. Four were boys.

China, with a headcount of 1.34 billion people, is the world’s most populous nation, in spite of a one-child policy imposed by the government 30 years ago.

“Overpopulation remains one of the major challenges to social and economic development,” Li Bin, director of the State Population and Family Planning Commission, told the official Xinhua News Agency. He said the population of China would hit 1.45 billion in 2020.

There is a concern that the policy will mean there won’t be enough young Chinese to support its enormous elderly population.

China also favours sons, and as such, there is an estimated 43 million fewer girls than there should be, given the overall population.

India, with 1.2 billion people, is expected to overtake China around 2030 when the Indian population reaches an estimated 1.6 billion.