The world’s first-ever sperm race is on deck and it’s shaping up to be a heavyweight fight … with plenty of trash talk on the eve of the main event.

Two young sperm donors, Tristan from USC and Asher from UCLA, are preparing to do battle in Friday’s live event at the Hollywood Palladium … so they joined us on “TMZ Live” Thursday to give us some insight into what it’s like being full-blown sperm athletes.

Tristan and Asher say healthy lifestyles and diets are key to getting their little swimmers ready for the big race … and abstinence is coming in to play too … just like before a big boxing match.

There’s a lot of science going into the Sperm Racing startup Tristan and Asher are competing in … and that includes plenty of lab tests.

Tristan says his medicals show he’s got way more testosterone than Asher … and he’s predicting his high T will get his sperm across the finish line first … though Asher’s not backing down and is firing back with a strong rebuttal.

Friday’s race is expected to draw over 1,000 people … and there will be a synchronized start before Tristan and Asher’s sperm race through a track mimicking the female reproductive system … complete with chemical cues and fluid dynamics.