Birth rates bounce around due to a bunch of different factors, but every so often, one event can spur a baby boom. While the most famous one occurred after World War II, sharp increases in birth rates have been caused by everything from soccer games to Communist decrees.

Some of these booms changed the course of a nation, while others are amusing demographic footnotes — and humans aren't the only one who can experience them.

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Take a look at seven events that caused their own population spikes.

1. World War II

The World War II Memorial in Washington, D.C., with legacy of the Baby Boomer generation. Image: Flickr, catface3

The end of World War II set off a massive spike in birth rates, especially in the United States, where the combination of peace, prosperity and the homecoming of thousands of young American men created the Baby Boom Generation.

Between 1946 and 1964, 74.6 million babies were born in the U.S., thanks to a few economic conditions and government programs that made it easier and safer for Americans to start families. The industrial demands of the war fueled an explosion of American manufacturing, and the factories that once made artillery and tanks later churned out cheaper automobiles and toasters.

As the economy boomed, the GI Bill also helped returning soldiers find affordable homes, solid jobs, subsidized education and vocational training. This gave them enough financial security to settle down and start families.

2. World War I

Making a new, stronger generation of countrymen and women is as patriotic as it gets. Image: Flickr, Daryl Williams

Roughly 16 million people died in World War I, which ended in 1918. In 1920, about 1.1 million babies were born in the UK, all as the Spanish flu pandemic that killed 50-100 million people was winding down. It's hard to pinpoint the exact cause of the boom, but the spike in birth rate was unprecedented.

3. The Romanian abortion ban

In 1967, Nicolae Ceaușescu decided Romania's birth rate was too low. To change this, the general secretary of the country's Communist Party issued Decree 770, which banned abortion and the sale of contraception. The goal was to increase the Romanian population from 23 million people to 30 million, and the country's birth rate spiked from 14.3 births per 1,000 to 27.4 in one year.

However, the mandate created a disaffected generation of children who felt rejected and were often abandoned by families who couldn't afford to take care of them. In addition, 9,000 Romanian women died of complications from illegal abortions, and the abortion rate actually increased between 1979 and 1989 when the ban ended, except for a decline between 1984 and 1985.

4. FC Barcelona's win in the 2009 UEFA Champions League semi-finals

Andres Iniesta: The namesake of a mini-generation. Image: Flickr, Marc Puig i Perez

Die-hard sports fans will sometimes name their children after their favorite players. It's a lot less common for a part of a generation to be named in honor of one.

A brief sports explainer for the less devout before we begin: The UEFA Champions League is a yearly soccer tournament that pits the best teams from European leagues against each other. FC Barcelona is a Spanish soccer team that plays in, well, Barcelona. Current players whose names you may remember from watching this summer's World Cup include Argentine superstar Lionel Messi, Uruguayan serial biter Luis Suarez and Brazilian wonder-child Neymar.

In May 2009, FC Barcelona made it to the semi-finals against London-based Chelsea, and won on a last-minute goal from Andres Iniesta. There was much rejoicing, and nine months later, the birth rate in Barcelona bumped 16% higher than usual for February.

These babies are nicknamed "The Iniesta Generation," and even though they don't actually qualify as a demographic generation, it makes for a hell of "where were you when" story for Mom and Dad.

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5. Corn

Sweet, delicious baby-making fuel. Image: Flickr, Michael Dorausch

OK, so there's a little more to it than that. Researchers at Washington State University found that the American Southwest experienced what are likely the highest birth rates in history between 1100 B.C. and 500 A.D.

These rates, which the research team attributes to advances in corn production, were so high and unsustainable, they triggered an overpopulation crisis. The southwestern population started to plummet in 1300, until the area was almost devoid of human life.

6. Hurricane Sandy

Hurricane Sandy left the city covered in flood water and half of Manhattan without power. Image: Flickr, Chris Ford

Baby booms are frequently and often inaccurately reported after natural disasters, and most of the evidence for the post-Sandy spike is anecdotal. However, two New Jersey hospitals experienced 34% and 20% increases in deliveries nine months after the storm hit the New York metro area in late October 2012.

While some post-storm baby booms are just natural fluctuations in birth rates, a study conducted by three professors through Johns Hopkins University found that natural disasters can lead to statistically significant birth rate increases.

This all depends on how severe the disaster is, since people fleeing for their lives have little ability or desire to do the necessary deed. The study found that storms are most likely to lead to baby booms in areas where activity and movement are limited along with potential danger and property damage.

7. The U.S. government shutdown?

While shameful moments in American history don't automatically qualify as natural disasters, many in the Washington, D.C. area thought 2013's federal government shutdown had a similar baby boom effect. Like the post-Sandy spike, the evidence here is anecdotal, and it's not like being furloughed prevents you from doing anything else but "being" with your significant other.

Even so, Sibley Memorial Hospital in Washington, D.C., saw an additional three births per day in July, and Virginia Hospital Center in Arlington delivered 99 more babies in April, May and June 2014 than it did during the same time in 2013, according to ABC.

BONUS: Cute animal baby boom

Red Panda baby booms are the best baby booms. Image: Flickr, Janice Sveda, Smithsonian Conservation Biology Institute

While the government shutdown baby boom in only anecdotal, the baby boom at the National Zoo in D.C. is very real and very adorable. This spring, 31 endangered animal babies — including two red pandas, a fishing cat and a leaf-tailed gecko — were born at the Zoo, and you can see pictures of a bunch of the little critters here.