At what age do you think children should be taught about sex?

These days, you hear alot parents telling you that they find it difficult to talk to thier children about sex, hmmmmmm I know it can be a be tasky but you just have to tell them else they will get to know about if from friends the wrong way.
Every child is different, but here is a rough guide to what children should be able to understand about sex and reproduction at different ages.

Infancy: Up to two years
Toddlers should be able to name all the body
parts including the genitals.
Most two-year-olds know the difference between
male and female, and can usually figure out if a
person is male or female.

Early childhood: Two to five years old
Children should understand the very basics of
reproduction: a man and a woman make a baby
together, and the baby grows in the woman’s
uterus.
Children should understand their body is their
own. Teach them about privacy around body
issues. They should know other people can touch
them in some ways but not other ways.

Middle childhood: Five to eight years old
Children should have a basic understanding that
some people are heterosexual, homosexual, or
bisexual. They should also know what the role of
sexuality is in relationships.
Children should know about the basic social
conventions of privacy, nudity, and respect for
others in relationships.
Children should be taught the basics about
puberty towards the end of this age span, as a
number of children will experience some pubertal
development before age 10.
Children’s understanding of human reproduction
should continue. This may include the role of
sexual intercourse.

Tween years: Nine to 12 years old
In addition to reinforcing all the things above they
have already learned, tweens should be taught
about safer sex and contraception.
Tweens should understand what makes a positive
relationship and what makes for a bad one.
Tweens should also learn to judge whether
depictions of sex and sexuality in the media are
true or false, realistic or not, and whether they
are positive or negative.

Teenagers: 13 to 18 years old
Teens are generally very private people. However,
if parents have spoken to their child early about
sex increases the chance that teens will approach
parents when difficult or dangerous things come
up.