This whole thing is a myth. Dr Goldstein is the quack who came up with this crap about 5 or 6 years ago and the news jumped all over it. He later admited he was wrong but no one cared - apologies don't make the news.

The truth is....

Bike saddles have nothing to do with numbness in the genitalia. Poor bike fit is the cause. If the reach is too long, or especially if the handlebar is too low relative to the saddle (like on most bikes being sold today) you will lean to far forward and squish your sexual parts.

I had numbness problems in the mid-1990's but solved them with a shorter, higher stem.