[Ladyflash]

We constantly tout that maca has an effect on our sex hormones, but I do believe this is actually a myth. It may be a misunderstanding because of how highly maca benefits the body. The surplus of nutrients it gives our body may simply give the body the tools it needs to achieve homeostasis at a much better and more efficient rate.

I'm going to quote wikipedia since it summarizes this.
(I know, I know, Wikipedia can be edited and all, but I choose Wikipedia because it actually has and lists SOURCES supporting each statement it makes)

Health effects

Maca is consumed as food for humans and livestock, suggesting any risk from consumption is rather minimal. It is considered safe to eat as any other vegetable food. However, maca does contain glucosinolates, which can cause goiters when high consumption is combined with a diet low in iodine. This being said, darker colored maca roots (red, purple, black) contain significant amounts of natural iodine, a 10-gram serving of dried maca generally containing 52 µg of iodine.[1] Though this is common in other foods with high levels of glucosinolate, it is uncertain if maca consumption can cause or worsen a goiter.[17] Maca has been shown to reduce enlarged prostate glands in rats.[5][18][19]

Small-scale clinical trials performed in men have shown that maca extracts can heighten libido and improve semen quality.[20][21] A small double-blind, randomized, parallel group dose-finding pilot study has shown that Maca root may alleviate SSRI-induced sexual dysfunction.[22] Maca does not affect sex hormone levels in humans, and has not been shown to act on hormones directly. It has been presumed that maca's effects may be due to the root's unique nutritional profile, which provides optimum levels of nutrients utilized by the body's endocrine system.[23] In addition, maca has been shown to increase mating behavior in male mice and rats.[24] A recent review states "Randomized clinical trials have shown that maca has favorable effects on energy and mood, may decrease anxiety and improve sexual desire. Maca has also been shown to improve sperm production, sperm motility, and semen volume."[19]

Source