ISO possible siblings whose bf was in the navy during vietnam

I am looking for any possible siblings that may have been born during the vietnam war. May father was in the navy and at one point was stationed in Oregon. He is of Czech descent has brown hair and blue eyes is approximately 6 ft and was born in California. His first name is Joe. If you are searching for your birthfather and this description sounds familier, please let me know. I have always wondered if I have any siblings out there.:D