So many factors go into falling in love, but new studies prove that it may be less about romance and more about science and that it all boils down to your five senses.
For Terry Ornelas falling in love was a scene straight out of a movie.
When she spotted Daniel Woodroffe across a crowded restaurant in Austin, Texas, she said "my insides just dissolved into butterflies."
"When he smiled it just made me so happy and it was such a strange emotion to have with somebody you've never spoken to before have met before I couldn't explain it," Ornelas said.
Falling in love is driven by the desire to reproduce, and researchers say when it comes to finding the right mate, science is providing new clues as to how the brain and the five senses collide to create the perfect storm of love.
"You slowly winnow out those individuals who don't look the part, feel the part, touch the part and you are left with the kind of person who you think is right for you. And at that point, boom!" said Rutgers University anthropology professor Helen Fisher.
Researchers say there is some truth to "love at first sight."
"A high forehead, big eyes, a small nose, certainly clear skin. All of these things suggest youth because that's the way a baby looks," said Jeffrey Kluger, the science editor at Time magazine.
There is also "love at first taste and smell." The first kiss can literally serve as a taste test for true love.
"There can be testosterone in men's saliva. The man is sort of slipping a chemical mickey that acts as an aphrodisiac on the woman," Kluger said.
That kiss could potentially determine whether a couple's genes are compatible enough to produce a healthy offspring.
When you kiss, a cluster of genes called MHC are exchanged in the mouth through saliva. If your genes are too similar there could be problems carrying a baby to term.
The Nose Knows When It Comes to Love
Perhaps the most primal indicator of attraction comes from your nose.
Your partner has to smell right to you. Pheromones, the chemicals that attract the opposite sex, are important, and even the timing of a woman's cycle plays a role.
In a study of exotic dancers, women who were ovulating made an average of $70 in tips an hour. Those who were in the nonfertile part of their cycle only made $35.
A deep, confident voice is also attractive to women because it is filled with testosterone.
One study showed the richer a man's voice, the more children he had.
"Touch is the mother of the senses, a huge amount of the brain becomes activated when you are touched or feel somebody else's touch," Fisher said.
What happens when love goes wrong? Scientists say the birth control pill may cause a woman to pick the wrong mate, because altered hormones mess with nature. When she's on the pill, she likes him. When she's off, he may no longer be Mr. Right.
Enduring an emotional crisis together such as a death or a plane crash can make people think they're in love even if they're not. Alcohol or drugs can also confuse things.
Having sex too early in the relationship can also be seen as unattractive, and therefore, prevent a good thing from happening in the first place.
But for Ornelas and Woodroffe, who are getting married in March, they chalk up their love connection more to luck than science.
"I used to play the lottery all the time but I feel I don't have to anymore because I know it sounds girly, but I feel I have won in the universal pool of love," Ornelas said.
You can read more about the science of love in this week's Time magazine, on newsstands Friday.