Good question! Height is a trait that is about 60-80% down to genetics. So what I mean by that is that it is mostly controlled by parents passing it on to children. But different factors like nutrition and exercise all play a role in the other 20-40% that decides what height a person will be 🙂
It has also changed over the centuries – no doubt due to nutrition and the like – for instance, since about 1850’s, average height in industrialised countries has increased by approx. 3.9 inches. Next time you are in a old stately home or castle (such as Kilkenny castle), look at the small size of the beds compared to modern times!
Issues of increasing human height is also a topic of discussions around the ethics of genetic enhancement. Would it be self-defeating, if all wanted it? Is tall better in the first place? Sometimes there are very difficult ‘grey areas’ where an intervention on height would be considered a treatment or an enhancement – see the example of human growth hormone here: https://www.genome.gov/10004767/genetic-enhancement/