this is "nightline." tonight -- >> get out of the water! >> shark attack on the california coast. for one unsuspecting beachgoer things went very long very fast. >> you saw it coming at you. >> lunged right at my chest. >> the horrifying moment when he found himself in the jaws of a great white shark. >> you could just hear everything crunch. >> with more sharks than ever coming to our shores are we in more danger? >> oh, [ bleep ]. jessica simpson and eric johnson sure seem to be a perfect match. but is there a way to predict whether their love will really be forever? controversial new science suggests finding true love may be as simple as this. constitute secret to decoding love be in your dna?

and things are heating up as the sexiest athletes bare it all. from gold medal olympians to this "dancing with the stars" darling. we go behind the scenes for an inside look at this year's espn the magazine body issue. first, ""nightline" five." >> number one in 60 seconds.

good evening and thanks for joining us. as we enter the height of this hot, humid summer, more and more of us will be heading to the beach. but it's not just more swimmers. there are also more sharks than ever near our shores. tonight after one man nearly dies in the jaws of a great white, a new warning from the california city, a 60-day fishing prohibition, while they investigate the latest attack. here's abc's nick watts. >> get out of the water! shark! >> reporter: this shaky video shot from the pier captures the terrifying moment a shark thrashing, then steve robles screams. his morning swim turned into a nightmare. shark attack on a busy beach, july fourth weekend. >> you saw it coming at you. >> it made a real fast, sharp left turn and lunged right at my chest. you could just hear everything

crunch. >> reporter: people on land realized what just happened. >> oh [ bleep ]! >> reporter: fellow swimmers and surfers got robles ashore on this bloody surfboard. >> and i was screaming and screaming. and crying and screaming. and i was holding on to my cut. >> reporter: the horrifying wounds left behind. the shark, a seven or eight-foot juvenile, was mad. >> right here! >> reporter: he'd been hit by a fisherman on the pier when steve, a long-distance swimmer, got in the way. >> i grabbed its nose with this hand. and tried to pry it off of my chest. i was staring at the shark eyeball to eyeball, literally like right here. it was the most frightening thing i ever -- anyone could ever experience. >> reporter: he punched the shark in the nose a bit bit onc more and disappeared. >> what was going through your mind? >> i didn't want to die. just -- i was scared. i was -- i was panicked.

>> don't worry, don't worry, it's over. >> reporter: at manhattan beach sharks are spotted nearly every day by audacious paddle boarders. this is the first time one has attacked here. new studies show the great white population is increasing on both coasts. conservation efforts are working. in fact, the great white population in american waters is up 42% since 1997. and so are sightings. last week, a 12-footer was spotted off a cape cod vacation spot. days earlier an 18-footer spotted by fishermen just a few mile away. shark attacks are still extremely rare. there were just 47 in american waters last year, only one fatality. >> throughout the world it's actually very rare, considering how many people enter the water, to how many times the great whites actually swim by. very, very, very rare. >> reporter: your odds of getting killed by a shark at the

beach are 200 million to 1. >> sharks, we are not on their menu. >> reporter: how best to avoid being the next steve robles? the golden rule -- don't be an idiot. do not an tag news a shark. you don't bother them, chances are they will not bother you. but more and more it seems people are taking chances with sharks. just to get a glimpse or even a close-up encounter. youtube is filled with amateur videos like this. >> [ bleep ]. he's checking me out. whoo! oh my god, right under the board. >> reporter: paddle boarders chasing sharks with cam rath right here at manhattan beach where robles just got bit. >> we saw a big, dark shape. yep, here he is. >> reporter: surfers armed with go pros risking their safety for video proof of their adventures. >> that's a beautiful shark, wow. >> reporter: there's even an annual event from discovery:

shark week fueling our fascinati fascination. here's a young great white in one of their upcoming specials. similar to the one robles encountered. >> juveniles, but they're going for these birds that are on the surface. >> reporter: it's believed these juveniles come to the surface for hunting practice. shark mania as it were has spawned a new crop of shark junkies drawn to the danger and thrill. sean harrington is trying to create a viral video to promote his clothing line and he admits it went a bit wrong. >> i seen the shark coming for me, i just threw the bird cage behind my legs and pretty much just saved me from probably grabbing my legs. i've got to thank the bird cage, really. >> reporter: check out this florida teen who hitched a ride on a whale shark last summer. >> i decided that, you know what, i should maybe try and swim with him. because i might not be able to do it ever again.

>> you're [ bleep ] crazy. >> reporter: this is a nantucket fisherman who grabbed a 200-pound sand shark in the surf. >> i think people just kind oftc it seems wild, running into the water and grabbing a shark by its tail. >> reporter: there's a whole new industry, shark tourism, worth $300 million a year and growing. i went cage driving with great whites in africa a couple of years ago -- but even that's old hat these days. matt gutman went diving with tiger shark in the ba ham mays wearing nothing but a wet suit. what to do if on that rare occasion you're in fear of being ashacked by a shark? first up, if you see one and he's not lunging at you, swim calmly to shore. >> they go under surfers, we see them jump out of the water, nothing really happens. >> reporter: if the shark attacks fight back. punch it on the nose like steve reasons d

robles did. >> it was instinctive. >> it has all its electrical pulses in its nose. that will whack out the shark. unfortunately, the teeth are close to the nose. >> reporter: if it bites, gouge at its gills andize. >> you have to keep a cool mind. if you can, that's the best way to do it. >> reporter: back to steve robles, he was just in the worst place at the worst time. >> shark! get out of the water! >> reporter: juvenile white dozen not attack humans. this apparently only the second recorded case. and robles doesn't blame the shark. he blames the fisher machine. >> it was that guy that was agitating that shark. that caused all this. >> reporter: many beachgoers this weekend agree with robles. >> sounds like out of fear he attacked a person because he was scared for his life. >> putting surfers' lives in danger shouldn't be allowed. i think it should be banned. >> reporter: some eyewitnesses say they've seen fishermen purposefully attracting sharks. >> fishermen like to have the thrill of catching the fish.

the big fish. the fighting of the fish. >> reporter: which takes us back to the golden rule. don't antagonize them and chances are they won't attack you or anyone else. >> i just got really lucky. i'm getting a second chance. >> reporter: for "nightline," nick watt, abc news, manhattan beach, california. next, the business of finding love is a multi-billion dollar industry. what if the key to unlocking love is in your dna? sexy athletes getting naked for this year's espn the magazine's body issue. nobody told us to expect it... intercourse that's painful due to menopausal changes. the problem isn't likely to go away... ...on its own. so it's time we do something about it. and there's help. premarin vaginal cream. a prescription that does what no over-the-counter product was designed to do. it provides estrogens

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from matchmakers to online dating, helping you find love is a huge business. what if the secret is something rooted in your dna? and there's actually a way to unlock it? here's abe's bianna golodryga. >> reporter: by the time jessica simpson and eric johnson walked down the aisle this weekend, we already knew they had great chemistry together. after all, they've got two kids to prove it. right? but the question is, do they have what it takes to stay together? >> love, everyone wants it but not everyone finds it. >> reporter: even the millionaire matchmaker will tell you -- >> if he didn't have money tomorrow, would i date him? no, yawn, he'd put me to sleep. >> reporter: money can't always buy you long-lasting love. >> mr. serial dater. likes all the candy in the candy store, can't decide what flavor to take home with you.

>> you're not a 10. >> reporter: what if the secret to knowing if mr. right is more than just mr. right now, is assism as this? >> you're not a good spitter. >> reporter: what if in the search for compatibility it's what's inside that counts? way inside? >> not just finding out that your relationship problems are actually in your genes and you can solve them. >> reporter: instant chemistry is one of the newest matchmaking services and it's all based on the idea that your genes determine compatibility. sounds good, right? we decided to put it to the test. couple number one, meet maria and taso, both greek-american and they've been happily[>ñ mard for five years. but it wasn't love at first sight. >> honestly? i could not imagine my life with anyone else. but at the time, to me, he was just like your stereotypical greek man. >> reporter: now that she has two kids she's hoping she and

taso are genetically destined to be. >> i guess i'm a little nervous. if it shows that we're very much apart and we don't have a genetic makeup that would result in a fruitful partnership, you know. then i guess -- i don't know. it makes me nervous. not that it would be over. >> couple number two, hagan and katie met the old-fashioned way. >> we met at the office. >> i came in as an intern. >> he was an adult intern. >> reporter: so far, most matchmaking methods haven't impressed them. >> you can kind of cheat, like any personality test, but this is actually science. >> reporter: i couldn't resist dragging my own husband in for one more test. i've done it all, from ancestral genetic testing to a facial recognition test to see if peter and i really were picture perfect. >> 63% is a pretty good number. >> that is a match. >> great news for us, peter.

>> reporter: what makes instant chemistry different thon all the rest? >> usingn line dating it's easy to look at the person and say whether they're pretty. there's no real way if you're going to tell if you have chemistry with them. >> reporter: that's why these happily married scientists created this business. >> when you hear the term chemistry you think of sparks flying. you don't necessarily think of your dna being compatible. it is these genes that are leading to that spark and that sort of physical attraction. >> where are you, my little cabbage? >> reporter: pepe lepew may not have been far off. the idea behind skaent chemistry is our unique scents are what attracts us to each other. we're not just talking about perfume. that unique scent actually comes from genes in our immune system. and when it comes to those genes, opposites attract. >> if you have two people together with different immune systems and they have a child, the more diverse those genes are, the more chance the child has of withstanding different pathogens or infections.

>> reporter: basically, just like in the rest of the animal kingdom, we are naturally driven to find someone that we can have the healthiest kids with. but we all know finding that perfect match isn't all that easy. these scientists say this is where instant chemistry can help. all it takes is a bit of spit. >> i guess i'm ready to spit. >> all right, great. >> thank you for choosing instant chemistry. >> spit until the amount of saliva reaches the fill line. >> whoa. fill line? holy crap, that's a lot of saliva. >> shouldn't do this the first time you meet somebody. >> reporter: at home my husband volunteered his dna. >> i hope this worked. >> seal ship, done. >> reporter: now we wait. >> our fate lies in its hands. >> reporter: for $200 any couple can get a testing kit delivered to their door. it includes a personality assessment. instant chemistry has only been around since january. through partnerships with matchmaking services they say their product has results in

dozens of happily ever afters. but it is controversial. some scientists say there's just not enough data out there to support their claims. others say the test is bogus. >> there have been scientist hot said, of course your immune system and variabilities are going to be different, you come from different backgrounds. >> there's published scientific papers that have shown couples who are more dissimilar in immune system are more lily attracted to one another. >> reporter: our scores are in. drumroll, please. >> 98% genetic compatibility. >> that is crazy. >> good to know. glad i know. >> it's good also because we have two kids. so that means they have a good genetic makeup. i'm very happy. >> reporter: katie and hagan? >> oh! genetic compatibility, 10%? >> good thing they don't take it too seriously. >> so no kids? >> no kids, no kids. >> just keep your genes to yourself. >> reporter: it's our turn.

>> all right, the big moment's here, you ready? >> of course i'm ready. >> genetic compatibility is -- 60% for an overall average percentage of 64%. although i do have to say most long-lasting couples were found to have genetic compatibility higher than 74%, all hope is not lost. >> i'll take it. >> reporter: who cares about dna. i'll stick with the one i've got. >> could be worse. that's pretty good. still in love? yeah. next, what do michael phelps, amy purdy, and venus williams have in common? you fifteen percent or more on huh, fiftcar insurance.uld save yeah, everybody knows that. well, did you know that playing cards with kenny rogers gets old pretty fast? ♪ you got to know when to hold'em. ♪

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they are the finest athlete of our time. nfl stars to olympians. and they're taking it all off. why? here's abc's linsey davis. >> reporter: it is, after all what we come into the world wearing. our birthday suit. but when you put it on the cover of a magazine, it has the cover to shock, anger, intrigue, and sometimes inspire. >> we're not going out there just trying to be titillating, we're trying to prove a point about the athletic form. >> reporter: espn the magazine's sixth annual "body" issue, showcasing the world's most elite athletes, all posing tastefully nude. it didn't easy getting star

athletes to take their clothes off. >> they're human beings. as proud as they are of their bodies they're still anxious about the idea of getting naked in front of people for a photo shoot. >> reporter: five-time wimbledon champion venus williams recalls feeling a little shy. >> i was joking that i wish i would have like really just done 1,000 abs a day to compete with athletes that are just ripped. but i'm probably never going to be ripped. i'm powerful on the court, that's all that matters. >> reporter: but soon they forget the cameras are even there. >> in the first two or three frames, the athletes forget they're naked, they don't care that they're walking around naked on set, it gets very comfortable very quickly. >> reporter: 18-time olympic gold medalist michael phelps and "dancing with the stars" favorite amy purdy just some of the 22 athletes baring it all. 23-year-old hawaiian surfer beauty coco ho ditches the wet suit and surfs naked. >> sometimes it's the thrill of the wave you get, the adrenaline of a really good barrel. >> reporter: not all the bodies are young athletes.

78-year-old hall of fame golfer gary player was in last year's issue. and this year, 49-year-old light heavyweight world champion bernard hopkins, the oldest title winner. some of the photos have caused controversy. last year tennis star radovanska was dropped from a catholic youth group in poland for her immoral behavior. >> something we feel is severely offensive, we have a conversation about it, then we're glad it's generating that conversation. for her she was proud of her pictures. >> reporter: most of the athletes are fearless on set. the standout star from this year's shoot? >> certain yeserga baka was ups weren't more parts of his body to work out. >> reporter: whether on the field or on the set they come with their top game, ready to show the world what we're really made of. for "nightline" i'm linsey davis in new york.

>> thanks for watching abc news. "world news now" is coming up soon with overnight breaking news. tune into "good morning america" tomorrow. as always we're online at abcnews.com. star command, i'm detecting.ss of happiness. ...and the speed readings are off the chart!

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