I would be a little leery of these studies as there are so many uncontrollable variables that could come in to play causing infertility. One thing that may go along with the problems of some of the people in these studies could be their exposure to pesticides, which may cause infertility in males.
There is some research and evidence to support the idea that better more bountiful nutrition in early life does affect fertility factors. A study of two Guatamelan villages found that those children who received a higher nutritional intake via a supplemental source, showed that these children reached menses earlier and had an earlier average age of first births than the other village. The following is a link with more information.
I too would be cautious about such studies. There are to many variables to say food caused fertility problems. Early foods might cause an upset tummy, but most likely not fertility problems.
There were undertaken studies concerning the influence of the early life food over the fertility of individuals.
Some of these studies have based their conclusions, after an analysis of some records from 18thcentury, from Finland, concerning births data and crop yields of rye data.
The conclusions have shown that the individuals born in poor families, where rye and barely yields were low, did not reproduced in their entire life, the lack of food limiting the development of their reproductive system.