Another secret Rabbi Brody shares with us is that keeping niddah brings prosperity to a couple. [...] According to Kabbalah, there are several main spiritual pipelines, or channels, by which our sustenance is brought down from Above. [T]he main pipeline for prosperity is the wife. Therefore, the cleaner the pipe, the greater the channel is for receiving abundance from Hashem. For a husband to reach his full potential in his career and business ventures, the wife's soul must be a pure channel for abundance. I like to think of spiritual impurities as "spiritual cholesterol". They are unhealthy for the soul and body, as these blockages greatly diminish the amount of abundance that is able to reach it's intended destination.

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Regarding the husband, Rabbi Brody explains that instances of prostate cancer are significantly lower among men whose wives observe niddah. The same holds true for rates of uterine, ovarian, and cervical cancer.

There is another reason why it's called "family purity". The children that are born from such a pure and holy union are blessed in every way. "When two parents are pure channels, they impart their purity to their children," states Rabbi Brody. During the time of conception, Hashem acts as a partner with the parents in the creation of a new child. This child will be born with a healthy and balanced mental and emotional disposition, along with a sharp mind and a good heart. Conversely, children that are born of an impure union are more likely to suffer emotional and mental disorders, anxiety, and be more difficult to raise. This is because the child received the impurity from the parents at the time of conception.