The shortest answer would be they dont know how to. Because they dont know how their approach should be. Its not a fun thing to have such conversations between son and their mother. As this is the unspoken taboo, parents sometimes are hesitant because of them thinking that if they do have "the talk" any wrong indication might create a sense of perversion in their child.
If youve ever heard the words "oedipous complex" then you will immediately know what im talking about. Parents who know clearly about this asymmetric affection are more free to talk about sex in an approach that avoids all the vulgar and absurdities of sexuality. And when talking about sex its better to rather talk about sexuality as it covers a much broader term then the fixed act "sex". Because of the hesitancy of mothers or parents their child can get entangled in an unhealthy sexual relation. At a certain age when children are just crossing their puberty their sexuality will take the shape as they perceive it to be portrayed by others around them. Fear of "the talk" can lead to hectic issues that both the parents and children might suffer from. This known sub conscious complex of mothers always make them unwilling to talk about sex as it blurs the line about where to start from.. Thats the most common reason.
Except that cultural appropriation , social taboo, religious bindings and a intentional letting him learn from other boys are also other specific reasons that make mothers unwilling. Thats why my opinion is for mothers being more open while raising their children in a way thats not un-appropriate but sufficient to teach their sons everything befkre they jump into the dating world.. or to teach their daughters about how they should talk to their sons in a few decades can also be another alternative.
It's very simple, sex is a complicated issue and secondly it depends. Some parent, expecially African parents hardly tell their children about sex and telling them about sex means educating them on the advantages and the disadvantages, telling them about the changes it may bring to their lives and how it may take away the teenage life if eventually done or had without protection and that's why the rate of teenage pregnancy is higher in Africa than other continent because of the fact that they were not properly educated on sex.
Talking sex with children seems embarrassing. Some parent actually feels that sex as a topic is embarrassing they feel it's something too complicated for a child to hear or know as a result they refrain from teaching children sex education.
They feel that telling children about sex might corrupt them and make them want to have a feel of it therefore the best way to prevent it will be not talking to them about it, also sometimes mothers or parent in general usually feel their children are too young to know about sex the forget forget to acknowledge that from the age of thirteen children are beginning to develop and become curious and their hormones and attractions towards the opposite sex begins to develop and as a result of this, they need their parents to guide them through this stage.
The last one will be ignorance, sometimes parents or even mothers do not know that children needs sex education and as a result totally neglect this responsiblity as parents
Parenting is one very great task that humans would ever face. From the time a child is born, a lot if resources are put into their physical and mental well being but little or nothing is done about the emotional. Some parents just think that some how, the child would grow up to be a normal adult.
A child is not just a physical being. He has a soul that comprises his emotions and will. Parents make the mistake of focussing on the child's body. They shower the child with physical gifts, food, clothes and even money. They even help build the child mentally, sending them to good schools and to get friends in order to build their social life. But there's one thing they fail at. That is helping to build the child emotionally. They talk about everything else except Sex. Sex is seen as sacred and a taboo. Talk about it and the gods may strike you dead. Funny right?
They never talk about sex for several reasons:
1. It raises so much questions. No other subject raises more question than the subject of Sex. Humans are by nature very inquisitive. There's always this quest to know. So, beginning from childhood into adulthood Children begin asking questions about everything and anything. As they become teenagers, these questions are further propelled by development of secondary sexual organs. So much questions especially about the opposite Sex. At this stage, a lot of persons are willing to explore and find out for themselves. A lot of parents are either not sure how to go about it or how much would be too much such that they wouldn't be positioning the child for future disaster. They rather not talk about it.
2. Its a really embarrasing subject to address because of the numerous controversies ranging from religious to social background. The world has a view of Sex and religion too has. You cannot talk about Sex without having to make mention of sexually related terms. Most parents are too shy or embarrassed to address this.
3. Ignorance. Ignorance also play a major part in the reasons mothers are afraid to talk about Sex. A lot of persons are not well informed and in life, you can't give what you don't have. A lot of African mothers were forced into early marriage. They were either not in love with their partners or they were not ready. They even believe that they are initiating moral decadence in their children by talking about sex. So instead of talking about it, they rather warn sternly or make unhealthy competition, thereby destroying the child's self esteem. The children eventually grow up to learn from strangers and other adults who may explore their innocence and leave them devastated for life.
I remember growing up as a child in an average traditional home. You dare not mention Sex organs or body parts relating to Sex. I was even shy and embarrassed to talk about my body parts. It only became worse with religion doctrines inculcated. I grew up this way, never learning about Sex from my parents or siblings. Everything I knew about Sex both the good, bad and ugly were learnt from books, tv, radio and from peers and school teachers. if I I had peradventure missed it along the way, there was no way to tell. I could only rely on my instincts and I'm glad I didn't Miss it though.
The answer to this depends on what age the child has it. In addition, before saying anything to children, you need to know what they hear, see, and whether they care about what is happening. because the little ones in stock when we show we have the time they know about the sex