How to talk to sons about sex?

Hi I'm Gina. I'm mother of two wonderful 10 years sons. Their father has left us 8 years ago. I have a question, maybe some of you can help me? At what age should a parent teach their son about ‘sex’ if there is no father around or would it be better for the kid to have a male family member to do this? It really bothers me because i've found adult magazine in their room today. Should I talk to them by miself or ask my brother to do it? Hope someone had the same problem and can advise me anything. By the way, here is the photo of my sons: http://www.wesdfre.com/__media__/js/netsoltrademark.php?d=pasionmujeres.com/ladyboy/ - https://i.ibb.co/4ghm31h/main-qimg-2874a40311959b1bc7694d2f51400d8e-c.jpg

I dont have kid myself yet, but one of my older cousin had the similar problem. What we have found out is , it's much more effective to talk with the kid early and often in small portion. Try not confuse your kid with too much information at one time. It's also important to listen to the kid questions (Kids have different questions and concerns about sex at different ages. As your child gets older, the things you talk about will change). Even if you don’t agree with your child’s opinion, you need to listen carefully. By this way you can tell how much he allready know. It don't have to be one of those embarrassing "Sex talk" in movies and sitcom. Just take it slow. I hope I could help