But nothing is surer � while sex is one of the most popular conversation topics for teens and 20-somethings it remains largely taboo for those 50 and over. And this reluctance to talk about sex is part of the problem when trying to improve relationship and sexuality issues.
�What people don�t realise is that sex affects (everyone) whether we are having it or not,� the Curtin University graduate said.
�Sex is more than the physical act. It is an attitude and awareness that we bring into each relationship that we have, sexual or non-sexual.�
Ms Knudsen (24) set up her educational practice at Lifeskills Australia in January and has already noticed a trend among her small but growing list of clients. Many have been mature women asking how they can increase the level of intimacy in their significant relationship.
�Most have been in a relationship for more than 10 years and their husbands don�t realise that sex and intimacy are different,� she said.
�Their husbands think that having sex all the time is being intimate. But it�s more about touch and consideration and having a good friendship. At the start of a relationship it�s lustful and physical, but what lasts is having that friendship.�
Another trend is women�s libido.
�Many women think they have no sex drive and that something is wrong with. They don�t realise that this can change. Libido is not set in stone,� Ms Knudsen said.
�They are not weird or alone or a prude. Women are like an oven, not a light switch; they have to be warmed up. It�s not like flipping a switch, and that�s where intimacy comes in.�
Ms Knudsen�s interest in sexual education began as a secondary education student at university.
�I did one unit of sexology and I was hooked,� she said.
�I knew I would have to come back to it at some stage. It always stayed in the back of my mind.�
After finishing her education degree and working for six months at a private Perth girls� school, she went back to university to complete a postgraduate diploma of sexology.
�It was an itch I had to scratch. I do a lot of reading and research because it�s not just a job, it�s a passion,� she said.
�My generation talks about sex all the time but even people in their 30s and 40s have a different attitude. When they were growing up they were told not to talk or think about sex. There�s still a stigma.�
A worrying trend was that men were set on pleasing their women so that they achieved orgasm but it created a cult of pleasure that meant women who did not always climax were faulty or making their men feel incompetent, which caused tension.
�It comes down to education, talking and learning about sex. There is no such thing as normal,� she said.