Talk developed by college professor for pre-teen daughter to learn basic sex education.

1. Why your body changes… what’s
happening and what it means
By Dad

2. First start w/animals
• Most animals and plants need to combine
male and female “stuff” to make offspring
Male stuff = SPERM
Female stuff = EGG (also called an OVUM)
Each one (the female,
the male) has ½ the
genes needed to make a
new individual. That’s
why baby animals
usually look like a mix of
Mom and Dad.

3. For some animals it’s pretty easy!
• Frogs- the male rides around on the female
until she lays eggs, then he puts his sperm on
the pile of eggs.
• Some eggs will
turn into tadpoles,
if sperm find them
and fertilize them.

4. For mammals (including people) it’s a
little more complicated
• When mammals can reproduce (make offspring-
babies), that’s called ‘sexual maturity.’
• Mature mammals usually have a ‘mating season’
where the females become interested in mating,
and their bodies get ready to get pregnant. Males
get ready to help out.
• When our pet dogs and cats do this, it’s called
‘going into heat.’ (Penny won’t, she doesn’t have
those parts. She had surgery to get rid of them).

5. Some ways animals mate
There are different ways, but basically the
male and female get together and the male
puts his penis into the female’s vagina.
After some physical activity (rubbing the
penis in and out, usually) the male’s sperm
enter the female and start swimming to
find the eggs. If a sperm reaches an egg (or
a bunch reach a bunch of eggs- like in pigs
or dogs), that’s fertilization and the female
can get pregnant

6. Gestation (pregnancy) and birth
• The female will carry her offspring in her
uterus while they develop. Some animals carry
1 or 2, others can do dozens!
• When they are born (fully developed) they
come out thru their mom’s vagina, and she
will nurse them to feed them.
Elephant is pregnant for 22 months- 1 baby; pigs 4 months, lots!; mouse 20 days; lots

7. Reproduction and Sex in People
• Follows most of the same rules as animals,
with some important differences.
• People don’t have a ‘mating season.’ Once we
go through puberty, we’re always interested in
each other.
First we’ll go over our bodies,
Then talk about feelings and activities and more.

8. Female Reproductive Anatomy
• The female external reproductive structures include
the clitoris and two sets of labia
• The internal organs are a pair of gonads (the
OVARIES) and a system of ducts and chambers that
carry eggs and sperm and eventually, make a home
for the developing baby.

9. Fig. 46-10a
(Rectum)
Cervix
Oviduct
Ovary
Uterus
(Urinary bladder)
Pubic bone
Urethra
Shaft
Glans
Prepuce
Labia minora
Labia majora
Vagina
Clitoris
Vaginal opening & remains of
hymen

10. Fig. 46-10b
Ovaries
Oviduct also called Fallopian Tube
Follicles
Corpus luteum
Uterine wallUterus
Cervix
Endometrium
Vagina

11. Male Reproductive Anatomy
• The male’s external reproductive organs are the
scrotum and penis
• Internal organs are the gonads, which produce
sperm and hormones, and accessory glands which
make other stuff that helps the sperm swim

12. Fig. 46-11a
Seminal
vesicle
(behind
bladder)
Urethra
Scrotum
(Urinary
bladder)
Prostate gland
Bulbourethral
gland
Erectile tissue
of penis
Vas deferens
Epididymis
Testis

13. Fig. 46-11b
Seminal vesicle
(Rectum)
Vas deferens
Ejaculatory duct
Prostate gland
Bulbourethral gland
Vas deferens Epididymis
Testis
Scrotum
(Urinary
bladder)
(Urinary
duct)
(Pubic bone)
Erectile
tissue
Urethra
Glans
Prepuce
Penis

14. Testes
• The male gonads, or testes, consist of highly coiled
tubes surrounded by connective tissue
• Sperm form in these seminiferous tubules
• Leydig cells produce hormones and are scattered
between the tubules (hormones = chemicals that
influence how we act, and how our bodies develop.
Male hormones make men big, hairy, muscley, and
have deep voices.)

15. • Hormones closely link the two cycles of female
reproduction:
– Changes in the uterus define the menstrual cycle
(also called the uterine cycle)
– Changes in the ovaries define the ovarian cycle

16. Fig. 46-14a
Control by hypothalamus Inhibited by combination of
estradiol and progesterone
Stimulated by high levels
of estradiol
Inhibited by low levels of
estradiol
Hypothalamus
GnRH
Anterior pituitary
FSH LH
Pituitary gonadotropins
in blood
LH
FSH
FSH and LH stimulate
follicle to grow
LH surge triggers
ovulation
Ovarian cycle
Growing follicle Maturing
follicle
Corpus
luteum
Degenerating
corpus luteum
Follicular phase Ovulation Luteal phase
(a)
(b)
(c)
Days
0 5 10 14 15 20 25 28
| | | | | | | |
–
–
+

17. Fig. 46-14b
Ovarian hormones
in blood
Peak causes
LH surge
Estradiol level
very low
Estradiol Progesterone
Ovulation Progesterone and estra-
diol promote thickening
of endometrium
Uterine (menstrual) cycle
Endometrium
0 5 10 14 20 25 28
| | | | | | | |
Days
15
Menstrual flow phase Proliferative phase Secretory phase
(d)
(e)

18. Fig. 46-14
(a) Control by hypothalamus
Hypothalamus
GnRH
Anterior pituitary
1
Inhibited by combination of
estradiol and progesterone
Stimulated by high levels
of estradiol
Inhibited by low levels of
estradiol
2 FSH LH
Pituitary gonadotropins
in blood
(b)
6
FSH
LH
FSH and LH stimulate
follicle to grow
LH surge triggers
ovulation
3
Ovarian cycle 8(c) 7
Growing follicle Maturing
follicle
Corpus
luteum
Degenerating
corpus luteum
Follicular phase Ovulation Luteal phase
Estradiol secreted
by growing follicle in
increasing amounts
Progesterone and
estradiol secreted
by corpus luteum
4
Ovarian hormones
in blood
Peak causes
LH surge
(d)
5
Estradiol Progesterone 9
10
Estradiol level
very low
Progesterone and estra-
diol promote thickening
of endometrium
Uterine (menstrual) cycle
Endometrium
(e)
Menstrual flow phase Proliferative phase Secretory phase
Days
0 5 10 14 20 25 28
| | |
15
| | | | |
–
–
+

19. • Following ovulation, the follicular tissue left behind
transforms into the corpus luteum; this is the luteal
phase – this makes hormones that would help a
baby develop, if the woman get pregnant.
• The corpus luteum shrinks, and hormones decrease
Animation: Post Ovulation

20. The Menstrual Period
• Shedding of the endometrium during the
menstrual flow phase coordinates with the growth
of new ovarian follicles – that’s your PERIOD.
• Every month that a woman doesn’t get pregnant,
she should have a menstrual period (or just, period)
when some red bloodlike tissue comes out of her
vagina. This can last between 3 and 7 days.
– You can wear a pad in your panties, or a tampon inside
your vagina, to absorb the period blood. This keeps you
from staining your clothes.

21. • A new cycle begins if no embryo implants in the
endometrium. The period ends and a new egg
starts to develop in one of the ovaries.

22. Puberty body changes
• Your menstrual period is probably the biggest
deal
• Body changes you’ve been dealing with
already
– Getting breasts
– Hair in underarms and in pubic area
– Thicker hair on legs, arms
– Smellier sweat, in armpits and hair. (deodorant,
regular showers needed)

23. Menopause
• After about 500 month-long fertility cycles, human
females undergo menopause, the cessation of
ovulation and menstruation. This happens when a
woman is between 42 and 50 years old.

24. Sexual intercourse – how does it work?
Other words for sexual intercourse
• “Doing it”
• Making love
• The f-word
• Having sex
• Many, many other words and phrases are used
for it sexual intercourse. Most are pretty silly-
sounding. “Knocking boots?” “Shagging” Yeah,
those are pretty dumb.

25. • Two reactions predominate in both sexes
– Vasocongestion, the filling of tissue with blood (you
might see your skin get pink, or a penis get bigger and
‘harder’)
– Myotonia, increased muscle tension
• The sexual response cycle has four phases: excitement,
plateau, orgasm, and resolution
• Excitement prepares the penis and vagina for .sexual
intercourse.
© 2011 Pearson Education, Inc.
Human Sexual Response

26. • Direct stimulation of genitalia (touching of penis and
vagina, or touching them together) maintains the
plateau phase and prepares the vagina for receipt of
sperm
• Orgasm is characterized by rhythmic contractions of
reproductive structures
– In males, semen is first released into the urethra and
then ejaculated from the urethra
– In females, the uterus and outer vagina contract
– This is how the man’s sperm can get into the woman’s
vagina, then her uterus and fallopian tubes, swimming
to find an egg.
© 2011 Pearson Education, Inc.

27. • During the resolution phase, organs return to their
normal state and muscles relax
• People can feel relaxed, emotional, or both during this
stage.
© 2011 Pearson Education, Inc.

28. Concept 46.5: In placental mammals, an
embryo develops fully within the
mother’s uterus
• An egg develops into an embryo in a series of
predictable events
© 2011 Pearson Education, Inc.

29. Conception, Embryonic Development,
and Birth
• Conception, fertilization of an egg by a sperm, occurs
in the oviduct aka Fallopian Tube
• Pregnancy starts when the ZYGOTE (the new ball of
cells created by mixing sperm and eggs) implants in the
side of the uterus and starts to develop and grow.
© 2011 Pearson Education, Inc.

30. 5
4
1
2
3 Cleavage
Fertilization
Ovary
Ovulation
Uterus
Cleavage
continues
Implantation
Endometrium
(a) From ovulation to implantation
(b) Implantation of blastocyst
Endometrium
Cavity
Inner cell
mass
Blastocyst Trophoblast
Figure 46.15

31. • During its first 2 to 4 weeks, the embryo obtains
nutrients directly from the endometrium
• Meanwhile, the outer layer of the blastocyst, called
the trophoblast, mingles with the endometrium
and eventually forms the placenta
• Blood from the embryo travels to the placenta
through arteries of the umbilical cord and returns
via the umbilical vein

32. Fig. 46-16
Placenta
Uterus
Umbilical cord
Chorionic villus,
containing fetal
capillaries
Maternal blood
pools
Maternal
arteries
Maternal
veins
Maternal
portion
of placenta
Fetal arteriole
Fetal venule
Umbilical cord
Fetal
portion of
placenta
(chorion)
Umbilical
arteries
Umbilical
vein

33. • Splitting of the embryo during the first month of
development results in genetically identical twins
• Release and fertilization of two eggs results in
fraternal and genetically distinct twins

34. • The first trimester is the main period of
organogenesis, development of the body organs
• All the major structures are present by 8 weeks,
and the embryo is called a fetus

35. • Changes occur in the mother
– Growth of the placenta
– Stop of ovulation and the menstrual cycle
– Breast enlargement & widening of pelvic bones
(hips/pelvis change in 1 st pregnancy only)
– Nausea (sick stomach) is also very common

36. Fig. 46-17
(a) 5 weeks (b) 14 weeks (c) 20 weeks

37. Fig. 46-17a
(a) 5 weeks

38. Fig. 46-17b
(b) 14 weeks

39. Fig. 46-17c
(c) 20 weeks

40. Second Trimester
• During the second trimester
– The fetus grows and is very active
– The mother may feel fetal movements
– The uterus grows enough for the pregnancy to
become obvious

41. Third Trimester
• During the third trimester, the fetus grows and fills
the space within the embryonic membranes
• A complex interplay of local regulators and
hormones induces and regulates labor, the process
by which childbirth occurs

42. Fig. 46-19-1
Placenta
Umbilical cord
Uterus
Cervix
Dilation of the cervix1

43. Fig. 46-19-2
Expulsion: delivery of the infant2

44. Fig. 46-19-3
Delivery of the placenta
Uterus
Placenta
(detaching)
Umbilical
cord
3

45. Fig. 46-19-4
3
2
1 Dilation of the cervix
Placenta
Umbilical cord
Uterus
Cervix
Expulsion: delivery of the infant
Uterus
Placenta
(detaching)
Umbilical
cord
Delivery of the placenta

46. So this is SEX, and it is a big deal
• It’s where babies come from
• It affects how we behave (who you are
attracted to, how you act around them)
• It affects how we feel about ourselves
• It affects how people feel about each other

47. You will be attracted to some other
people
• It’s ‘liking’ someone but a little more intense…
you’ll think they are CUTE or you might want
to touch, hug or hold them much more than
just a regular friend you like.
• For girls, it will usually be boys, but not always
(attraction to your same sex is called
homosexuality, or being gay, or in girls, being a
lesbian)

48. Things that you might find attractive
• Cute face or body (or both)
• Talents or athletic skills
• A nice smile
• Niceness (some people
are so nice, you wanna
hug them, just saying)
• Smarts
• Smell good (Really!)
• Lots of things add up to being attracted to someone
else. And, it’s ok. There’s no ‘right’ or wrong’ person to
be attracted to. You’ll like who you like.

49. Why people have sex
• Good physical feelings. It feels good.
• Feeling close to your partner, that’s why it’s
called ‘making love.’ When you’re married or
in a grown-up, caring relationship, it can make
you feel closer, or be a way to show your love.
-But if you’re not sure how you feel about
someone, not always the best way to ‘test
it out.’
• Wanting to make a baby (really)

50. Why NOT to have sex
– You’re too young, or not ready.
– Your body belongs to you, and you shouldn’t share it in an
immature way. Not while you’re a kid, for sure.
– And not when somebody ELSE is pressuring you.
Somebody you care about might want to, but it’s not up to
them. It’s YOUR body.
• You don’t want or can’t handle the responsibility of:
– Getting pregnant- being a young Mom or Dad means, less
time for school (or a really long break), less chance to do
well
– Getting sick- there are diseases spread by sex that can hurt
you, make you sterile (can’t have babies) or even kill you.

51. What can go wrong?
• If you value your body more than someone else does, and
you have sex with them and they:
– Brag about it to their friends
– Treat you like trash afterwards (ignore you, be cruel to you)
– Expect more sexual activity than you want to do, later
– Leave you with a pregnancy/baby they won’t (or can’t- most
teenage boys, lots of young men, are just plain crappy as Dads)
help with (This is a REALLLLY bad one).
^^^ Let’s be serious. THIS one RUINS WOMEN’S LIVES.^^^
The problem is, it’s hard to be sure someone you like wants the
same as you, unless you know them REALLY well. And young
people, often don’t know WHAT they want. Lots of feelings can get
hurt, and hearts get broken this way. Once you’ve been hurt this
way, it can become more difficult to love and trust other people.

52. Catholic Church says:
• Sex outside marriage is a sin
– Sometimes called ‘fornication’ or ‘adultery’
• Sex is a beautiful gift from God that is meant
for marriage, to help make families

53. Does a pregnancy or baby happen
every time 2 people have sex?
• No. Sperm has to enter the woman at the
exact time the egg is coming down the
Fallopian tube (about 3 days in a month), and
they have to meet, fertilize, and then the little
zygote needs to implant in the woman’s
uterus for pregnancy to happen.
• Women and men can do things to keep this
from happening. That’s called BIRTH
CONTROL.

54. Birth Control
• Barriers- sometimes we put something
‘between’ the man and woman.
A “Cap” “Sponge” or
Diaphragm can go in
a woman’s vagina to
keep sperm out of
her uterus.

55. Hormonal Birth Control
• Many different medicines that change a
woman’s hormonal cycle, can keep the egg
from being released, and prevent pregnancy.
• This used to be just “The Pill” but now it can
be a shot, or a little plastic insert in a woman’s
arm or uterus.

56. What about men?
• No hormone pills for men (science needs to
work harder on that!)
• Men have one option: it’s called a condom
or ‘rubber’. It catches the semen and keeps
sperm from going in the man’s partner’s body.

57. Bonus for condoms:
• Condoms are the only birth control that’s
really any good for keeping GERMS from
traveling from penises to vaginas, or from
vaginas to penises. Not perfect, but can
prevent a lot of bad diseases if used correctly.
• Sometimes using a condom is called ‘safe sex’
or ‘safer sex’
• Without a condom, it’s called ‘unprotected
sex.’

58. What diseases?
• Chlamydia, syphilis, gonorrhea, pelvic
inflammatory disease and others- these are
painful and can make you *sterile* (unable to
have babies later, when you might want to)
• HIV- this is the virus that causes AIDS. AIDS
damages your immune system, and will kill you if
you don’t take powerful, unpleasant drugs for the
rest of your life. HIV positive (people with the
virus) people can live a long time now, but their
lives are much more difficult.

59. HPV virus
• This one can cause genital warts (painful ugly warts
that grow in your genital-private- areas)
• Some of them can also get further into your body and
cause cancer in your uterus or cervix (the area
between the vagina and uterus) later in life – like 10 or
20 or 30 years later.
• LOTS of people have this virus, it’s very hard to avoid if
you have sex with more than 1 person, or 1 person
who had sex with other people. Most people do that.
• BUT There’s a vaccine (2 shots) that you can take
before you become sexually active to prevent HPVs. It’s
like a cancer-preventer shot.

60. Sexual Assault and Rape
Your body belongs to you. Nobody has a right or is ok to touch
you on/near your private areas without your permission. Ever.
RAPE is what we call it when someone does sexual things to
someone who does not want to participate, or can’t say
whether they do or not, or is too young to say it’s ok.
In the law rape called ‘sexual assault.’ It is against the law. It
anybody does this, or threatens to, tell an adult, and get them
to take you to a hospital. This will let a real doctor collect
evidence about how someone broke the law touching you.
We usually think of it as a man raping a woman, but girls,
men, and boys can all be raped.

61. Sexual Harassment
• Sometimes people don’t attack you sexually on your
body, but with their words or behavior. This is called
sexual harassment.
• It can be dirty or insulting talk directed at you, in
person, or just near you (or even in social media) but
inappropriate. Often harassers will say ‘It’s just JOKES!’
Nope. Not if it makes you uncomfortable. You have the
right not to put up with it.
• Talk to a trusted adult if ANYBODY starts any of this
type of behavior, at home, school, work, anywhere. If
this adult does not make it stop- find a better adult.
You don’t have to tolerate sexual harassment.

62. Questions
I bet you have a million questions. They won’t all
be easy to answer, but I will try.