SHE was called the luckiest woman in the world.

But now that luck is being called into question by some who think that winning the lottery four times is more than just a coincidental spell of good fortune.

Joan R. Ginther from Texas won multiple million dollar payouts each time.

The reclusive Ms Ginther, 63, who has amassed a $US20 million ($19.7million) fortune through scratch cards, is a Stanford-educated maths genius who may have cracked the code that determines how winning tickets are distributed.

First, she won $5.4 million, then a decade later, she won $2 million, then two years later $3 million and in the summer of 2010, she hit a $10 million jackpot.

The odds of this has been calculated at one in 18 septillion and luck like this could only come once every quadrillion years.

Harper's Magazine reporter Nathaniel Rich recently wrote an article about Ms Ginther, which calls the the validity of her "luck" into question.

First, he points out, Ms Ginther is a former maths professor with a PhD from Stanford University specialising in statistics.

A professor at the Institute for the Study of Gambling and Commercial Gaming at the University of Nevada, Reno, told Mr Rich: "When something this unlikely happens in a casino, you arrest ‘em first and ask questions later".

Although Ms Ginther now lives in Las Vegas, she won all four of her lotteries in Texas.

Three of her wins, all in two-year intervals, were by scratch-off tickets bought at the same mini mart in the town of Bishop.

Mr Rich details the myriad ways in which Ms Ginther could have gamed the system - including the fact that she may have figured out the algorithm that determines where a winner is placed in each run of scratch-off tickets.

He believes that after Ms Ginther figured out the algorithm, it wouldn’t be difficult to determine where the tickets would be shipped, as the shipping schedule is apparently fixed, and there were a few sources she could have found it out from.

According to Forbes, the residents of Bishop, Texas, seem to believe God was behind it all.

The Texas Lottery Commission told Rich that Ms Ginther must have been "born under a lucky star", and that they don’t suspect foul play.

