DR. WALLACE: Why is the average man taller than the average woman? And my friend told me that an average guy is only 5-foot-9, and that seems really short to me for an average height.

I guess I go to too many basketball games, because I'm used to seeing tall guys all over the place! — I Thought It Would Be Taller, via email

I THOUGHT IT WOULD BE TALLER: Indeed, the average height for American men is 5 feet, 9 inches, so your friend is indeed correct on this fact. American men are slightly above average when it comes to global average male height. For the rest of the world excluding the USA, the average man stands 5 feet 7.5 inches tall.

Height for men and women is driven by genetics, yet environmental factors like nutrition and diseases also play a role in human height.

Women, interestingly, vary in average heights around the world in a wide range, as some parts of the world have women averaging 5 feet 1 inch tall, while others like Polynesia have women who average 5 feet 5 inches tall!

Men are taller in general than women due to having longer legs. One might guess that a longer torso might be a large factor, but in fact, it's the legs that drive the major differences between the respective height of men and women.

Researchers at the University of Helsinki, Finland identified a genetic variant on the X sex chromosome that accounts for height differences between the sexes. This chromosome drives the length of the legs.

OUR PARENTS DISAPPROVE AND DON'T GET ALONG!

DR. WALLACE: My guy and I are both college students finishing up the junior year of our studies. We've known each other for almost a year now, and on our actual wedding date, we will have been together for over a year.

I always envisioned a big, happy wedding with everyone happy and proud of us, but that's not going to be the case.

Without going into a lot of details, let me just tell you that neither set of our parents are happy that we are marrying each other. And to make matters worse, a few months ago we arranged a dinner with both sets of parents and ourselves at a nice local restaurant, but it was obvious that none of them were happy. In fact, our parents got snippy with each other! I was mortified and now we are in a tight and delicate spot.

My fiance and I have considered inviting only one set of our parents so that there will be no more fireworks between them, but we can't yet decide which ones to ask. And we also realize that neither of them might attend anyway, even if invited. What should we do in this situation? — Not Happy With This Development, via email

NOT HAPPY WITH THIS DEVELOPMENT: Well, they do know each other already, so my advice is to stop overthinking this matter and plan to invite each of them.

This way you'll not be excluding anyone, as that could have dire implications for you later on in life.

For example, if you were to have a child someday, and each of your sets of parents were to soften and be interested in seeing their grandchild, you wouldn't want the lack of an invitation to your wedding to become a "forever" sticking point for anyone.

All four of your parents are adults, and even though they are not thrilled at this point in time, that could change over the years. Invite everyone immediately, and just be sure to sit them at different tables at your wedding reception; I trust you'll make it through that day just fine with both sets of parents. After all, they'll all be in public and are very likely to be on their best behavior during your special day. And if one or both chooses not to attend, you'll have invited them and you can still reach out to them later as your life — and your family — moves forward.

Dr. Robert Wallace welcomes questions from readers. Although he is unable to reply to all of them individually, he will answer as many as possible in this column. Email him at rwallace@thegreatestgift.com. To find out more about Dr. Robert Wallace and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.

Photo credit: Foto Pettine at Unsplash