Is he sterile?

So me and my partner are trying to conceive, we've only been trying for a few months now but he has recently expressed to me that when he was younger he never really practiced safe sex at all, no condoms or pull out and the girls he dated weren't on BC. But they never got pregnant. He feels that he is sterile and that we won't be able to have a baby of our own. Advice please??! None will be turned away. Thank you!