Why is the new generation always and often taller than their parents?

 The phenomenon of each generation being taller than the previous one is often attributed to improvements in nutrition, healthcare, and living conditions. This trend is known as the "secular trend in height." Several factors contribute to the increase in height across generations:

1. **Nutrition:** Access to better nutrition plays a significant role in the increase in height. Improved agricultural practices, more diverse diets, and access to a greater variety of foods contribute to healthier growth and development.

2. **Healthcare:** Advances in healthcare, including better prenatal care, reduced infant mortality rates, and improved overall health, contribute to better growth and development. Diseases that may have stunted growth in previous generations are now more effectively treated or prevented.

3. **Medical Advances:** The discovery and implementation of vitamins and minerals essential for growth, such as Vitamin D and calcium, have played a crucial role in promoting bone health and overall development.

4. **Living Conditions:** General improvements in living conditions, such as cleaner water, better sanitation, and reduced exposure to environmental pollutants, have positively impacted health and growth.

5. **Economic Factors:** Economic prosperity and stability can also influence height trends. Societies with better economic conditions tend to have better access to healthcare, education, and nutrition, contributing to the overall well-being and height of the population.

6. **Genetics:** While environmental factors play a significant role, genetic factors also contribute to variations in height. However, the influence of genetics on height is typically more consistent within a population, and the observed increase in height across generations is often attributed to environmental factors.

It's essential to note that the rate of increase in height can vary across regions and populations. Different populations may experience different rates of growth due to variations in socioeconomic conditions, healthcare systems, and cultural factors.

The trend of increasing height across generations has been observed globally, but it is not uniform, and there are still variations in height among different populations and regions around the world.