New England Patriots' quarterback Tom Brady held the Vince Lombardi trophy as he was interviewed by Terry Bradshaw (L, obscured) after the Patriots defeated the Atlanta Falcons to win Super Bowl LI in Houston, Feb. 5, 2017. (REUTERS/Adrees Latif)

Between Lady Gaga jumping off the stage during her halftime performance and the New England Patriots completing the greatest ever Super Bowl LI comeback, the NFL's championship game was filled with a number of surprises. One of those moments took place off the field when Patriots star quarterback Tom Brady celebrated the win in part by giving his dad a peck on the lips.

Kissing between people dating or in love has long been considered normal and is encouraged in many modern-day cultures, but the stigma to smooch a family member on the lips, let alone one of the same sex, has remained largely negative. Several other public figures have been criticized in the past for pecking their children on the lips, including Patriots head coach Bill Belichick, who kissed his daughter after his team won the Super Bowl in 2015. The internet consequently blew up with negative opinions and memes about Belichick’s kiss.

Another celebrity that took the heat was Victoria Beckham, who kissed her daughter Harper on the lips and posted the photo on Instagram.

The topic of whether it is a normal practice for parents and children to give each other kisses on the lips has been debated, with some considering it an uncomfortable practice: "Normally with a member of your family you don't kiss on the lips unless it's your husband," social etiquette expert Liz Brewer told BBC News.

She added: "I would be uncomfortable doing that and I think most people would be. If [Victoria Beckham] feels it's appropriate, so be it. I wouldn't say it sets a particularly good example."

While there have been those who feel kissing your child on the lips is a social taboo, others have said that there is nothing wrong with the expression of love. Educational psychologist and writer Dr. Michele Borba told TODAY Parents that Beckham’s photo of love "should be cherished."

She continued: "Is there anything more glorious than a mom showing her love for her child?"