The magazine unveiled its annual swimsuit issue with models Nina Agdal, Lily Aldridge and Chrissy Teigen on the cover of its 50th anniversary edition, and it is likely to spark a fresh debate around the focus on athletic and healthy physiques.Agdal, 21, from Denmark, and Americans Teigen and Aldridge, both 28, are the latest models to win a spot on the cover of the magazine's swimsuit issue, which has boasted the likes of Heidi Klum, Elle Macpherson, Tyra Banks and Kate Upton on its cover early in their careers.The three models, wearing just bikini bottoms and knee-deep in light blue water, coyly turn their heads and smile with their backsides facing the camera on the cover.Aldridge, who is best known as a Victoria's Secret underwear model, is the first Sports Illustrated model to grace the cover in her first appearance in the magazine since Klum did so in 1998.The 50th anniversary cover that is seen by some 70 million readers in the magazine, online and on mobile devices was unveiled on ABC's late night talk show "Jimmy Kimmel Live."The cover, which was photographed by James Macari, was projected onto a screen before a crowd outside the show's studio on Hollywood Boulevard in the historical heart of the U.S. film business.The Sports Illustrated swimsuit edition will be released on February 18 and is the most widely read edition each year of the magazine, which is owned by Time Warner Inc. Being on the cover or inside its pages can launch a career for a model.Agdal has appeared in swimsuit edition for the third consecutive year while Teigen, who married R&B singer John Legend last year, has been photographed by Sports Illustrated for each of the past five years.It is also the first ensemble cover since 2006 and the fifth cover to have multiple models.This year's golden anniversary issue will feature 22 former models, including 1964 inaugural cover model Babette March, 1970s supermodel Cheryl Tiegs, 1980s cover models Kathy Ireland and Paulina Porizkova as well as recent cover models Brooklyn Decker and Petra Nemcova."Sports Illustrated models represent the girl next door, only pretty," Tiegs said at an event last month celebrating the issue's 50th anniversary."They are not thin. For the most part, they are very athletic and healthy," Tiegs, 66, added. "That is the image they we portray."Joining generations of swimwear models in the issue will be a pictorial spread of the plastic Barbie doll, who will appear in the black-and-white swimsuit the Mattel Inc figurine wore in her 1959 debut.In mimicking Sports Illustrated's famous swimsuit shoots, 70-year-old fashion and sports photographer Walter Iooss Jr. took the photos of Barbie.Built around the marketing slogan "unapologetic," the inclusion of Barbie in Sports Illustrated's swimsuit issue unites two brands long assailed by critics as promoting impossibly skinny looks and objectifying women.Sports Illustrated, which was first published in 1954, developed the swimsuit edition to help the magazine's slow sales in the wintertime but it became such a hit that it has been taken on and has steadily evolved.But, while the magazine's popularity is clear, this may prompt fresh debate regarding how it should be portrayed in modern society.Is this something that is worth celebrating? There is a debate to be had, no question about it.Is it a wonderful celebration of female athleticism and health or just an "unapologetic" example of objectifying women? Post your comments below...(uk.eurosport.yahoo.com)ANN.Az