My answer is NO. There are plenty of long term relationships that have lasted for years, even ended with marriage where two people decided to have sex on the first date.
I don't think its a gender thing. Its just a choice and depends on how both parties are feeling that night.
I feel that what is meant to be will be regardless of whether you sleep with the person early or not.
If its not the guy for you, it is what it is no matter what you do
If it is the guy for you, he is going to think an angel just fell from the sky no matter what