人類的多態性 (Polymorphism) 中，左撇子比起右撇子相對稀少的現象，已經存在數千年，在運動場上方面，特別是與競爭對手有交互作用的運動中，左撇子的優勢有明顯提升，例如網球棒球板球、擊劍等，過去有研究認為左撇子選手相對的比例，甚至提升到約30%，而且其中有多數的選手名列世界頂尖排名。在過去數十年來的網球場上，左撇子對戰右撇子技術上的優勢迷思主要有兩個：一、左撇子的正拍對峙右撇子的反拍；二、左撇子的左邊 (Ad side) 外角發球。然而，在本研究的探討中，對於高層級的左撇子網球選手，其正面的優勢都逐漸緩和與減少中，對於年終排名與大滿貫冠軍的比例，似乎也不再有相關的趨勢，因此，現代的網球選手，如果要主導網球場上的勝利，與是否為左撇子關係不大，而是關乎選手在場上如何表現。

The polymorphism in human handedness as the relative rarity of left-handers compared to right-handers persists since thousands of years. In interactive sports such as tennis, cricket or fencing, however, left-handers are significantly overrepresented with up to 30% and more left-handed athletes listed in the top world rankings. In past few decades in professional tennis, there are two technical advantages to tennis’ myth of righty-to-lefty match: (1) Lefty’s forehand to righty’s backhand; (2) Lefty serve wide from Ad side, to righty’s backhand However, here we discuss that the positive advantages of left-handed performance on high achievement in elite tennis was moderate and decreased over time. The left-handedness was, no longer seems associated with higher probability of attaining high year-end world ranking position and titles of Grand Slam Championship. Therefore, being a dominant tennis player is not usually because whether he is a lefty, but how he plays the ball.