[fr_freak]

If they are on the pill there won’t be any PMS (or accidental pregnancies) but requiring that is a whole nother ball of wax.

I don't know a whole lot about submarines. Do they recycle waste water? If so, then you will have the same problem with the sub water supply that you have with the water supply in the general population - high estrogen levels partly due to excreted material after taking hormone-based birth control. Do you want your sub guys getting regular doses of estrogen?

[HiTech RedNeck]

I believe power from the engine is used to desalinate seawater for drinking and cooking. Estrogens wouldn’t be the only problem here; antibiotics would be too.