This large review looked at data from many different studies to see if infertility connects to thyroid cancer. The team studied over 4.5 million people to find clear answers about this health question. They found that people who have trouble getting pregnant do have a higher risk of this type of cancer later in life.
When scientists looked at men and women separately, they saw different results. For men, the connection between infertility and thyroid cancer was very strong. For women, the link was still there but not as powerful. This means the reason for the trouble getting pregnant might matter for men more than for women.
The study also had some limits. The different studies used many different ways to measure things, which made it hard to compare them perfectly. Also, some smaller studies seemed to show bigger effects than larger ones. Even with these limits, the main finding stands: infertility is linked to a higher chance of thyroid cancer.