When WorldNetDaily.com columnist James Rutz wrote a well-researched column called Soy is making kids ‘gay,’ parents got angry. However, Harvard University researchers are now saying that eating just half a serving a day of soy-based food can interfere with a man’s hormones and lower sperm count. Now, women and men are listening.

The research published online Wednesday in the journal Human Reproduction suggests that soy increases estrogen activity, which may have a negative effect on sperm production and also interfere with other hormonal signals.

Researchers analyzed the intake of 15 soy-based foods by 99 men who went to a fertility clinic between 2000 and 2006. The participants were asked how much and how often in the prior three months they had eaten soy-rich foods including: tofu, tempeh, tofu or soy sausages, bacon, soy milk, cheese, yogurt, ice cream and other soy products such as drinks, powders and energy bars.

Because different foods have different levels of isoflavones in them, the researchers set a standard for serving sizes of particular foods. Then they divided the men into groups according to soy consumption levels.