❓Can eating vegetarian cause infertility or affect fertility?

There's no reliable evidence that a well-planned vegetarian diet itself causes infertility. In fact, research shows that a diet centered on plant protein with plenty of whole grains and healthy fats is actually associated with a lower risk of ovulatory infertility. The nutrition-related factors that can genuinely affect fertility are things like: severe, prolonged calorie or nutrient deficiency (extreme dieting or too-low body fat directly affects hormones and ovulation), iron-deficiency anemia, long-term B12 deficiency, and being significantly underweight or overweight — and these issues show up in omnivores too, they're not unique to vegetarians. Whether or not you eat vegetarian, it's generally recommended to take folic acid when trying to conceive; vegetarians should additionally make sure they're getting steady intake of B12, iron, zinc, and DHA, and if needed, see a nutrition clinic to check specific markers, rather than simply chalking fertility issues up to "eating vegetarian." That kind of attribution isn't backed by evidence, and it risks distracting from the actual cause that needs to be investigated.