Parents give milk to their children because it makes them taller. See e.g.

https://www.tandfonline.com/doi/abs/10.1080/0301446080268046...

https://academic.oup.com/advances/article-abstract/10/suppl_... (a "maybe", but also increased mineralization)

https://cebp.aacrjournals.org/content/18/6/1881.short

https://www.sciencedirect.com/science/article/pii/S1570677X1...

https://search.informit.com.au/documentSummary;dn=2867428133...