Homosexuality (gay / lesbian) has recently been taken off the diagnostic manual used by psychiatrists. It is now considered normal in many developed countries. Gay and lesbian marriages are quite common in some countries nowadays,. Answering your specific question, children react to different things based on their genes and environment. Some kids may be genetically more prone to take risks and others may have a more cautious personality. The exposure to pornographic material may result in different reactions in different children, usually based on their individual personality and past experiences. We cannot always protect children from such experiences. We need to be open and honest with them when we educate them on these issues and create an environment where they are comfortable to discuss any such issues with us. Your parental anxiety is very common and shared by many parents with kids in that age group.