According to significant listing websites, the number of cryptocurrencies that are currently in existence is slightly over 5000. However, there can be an infinite number of cryptocurrencies because the cryptocurrency code is an open source. This means any person can use the code to create their unique type of cryptocurrency.
Now, about all cryptocurrencies being genuine, just like with other forms of exchange, scammers always look for a way to defraud people. They do this by creating fake cryptocurrencies and fronting them as replacements for bitcoin. They present them as the latest cryptocurrencies and as good as bitcoins and therefore safe to invest in. One such scenario involved My Big Coin, where investors were conned 6 million dollars.