Risk of accidental pregnancy BEST case scenario assuming PERFECT use
            Per Year (assuming 100 sex acts)    Per Act
No protection  8 in 10 (1 in 1.25)           1 in 125
Condoms                 1 in 50              1 in 5,000
Birth Control           1 in 333             1 in 33,300
Condoms & Birth Control 1 in 1,665,000       1 in 166,500,000*

Given 100,000,000 women of child bearing age (ages 14-59*),
Unplanned pregnancies result: 100,000,000/1,665,000= 60

Risk of accidental pregnancy WORST case scenario assuming TYPICAL use
       Per Year (assuming 80 sex acts)        Per Act
No protection  8 in 10 (1 in 1.25)           1 in 125
Condoms                 1 in 6.6             1 in 533
Birth Control           1 in 12.5            1 in 1,000
Condoms & Birth Control 1 in 6,666           1 in 533,333

533*1000=533,333
533,333/80=6,666
Unplanned pregnancies result: 100,000,000/6,666=15,000

Pregnancy rates of different contraceptives are from:
Comparison Of Birth Control Effectiveness: Number of Pregnancies per
100 Women During First Year of Use
http://www.plannedparenthood.org/pp2/portal/files/portal/medicalinfo/birthcontro
l/pub-birth-control-02.xml
&  more info here:
http://www.aafp.org/afp/20040215/853.html

Data does not say how many times couples are assumed to have sex, so
based on information gathered elsewhere, I estimated 80-100 times to
concoct best and worst case scenarios.

Currently there are an average 1 million abortions per year
http://www.infoplease.com/ipa/A0764203.html
http://www.nrlc.org/abortion/facts/abortionstats.html

48% of all U.S. pregnancies (and 78% of teen pregnancies) are an
unplanned
http://womensissues.about.com/cs/lifestyle/a/blunplannedpreg.htm

And 4 million new babies are born per year
http://www.census.gov/population/socdemo/fertility/fert94/htab02.txt

The below statistics give you an idea of how much safer contraception
makes us, and when compared to the numbers above, specifically how much
safer two forms of contraception make us.  Of course, not all women are
having sex, so all estimates of unplanned pregnancy above and below are
exaggerated.

unplanned pregnancies result with no contraception: 100,000,000/1.25 =
80,000,000
unplanned pregnancies result with condoms alone
(perfect use): 100,000,000/50 = 2,000,000,000
(typical use) 100,000,000/6.667 = 15,000,000
unplanned pregnancies result with birth control alone
(perfect use): 100,000,000/333=  300,300
(typical use) = 100,000,000/12.5 = 8,000,000

http://groups-beta.google.com/group/alt.abortion/browse_thread/thread/4294a36767
d26f88/103d6b66f152db01?q=PROMOTING+BIRTH+CONTROL+%3D+LESS+ABORTION&rnum=1&hl=en
#103d6b66f152db01

Rates of adolescent birth, abortion and pregnancy per year (per 1,000
women aged 15-19) and abortion ratio (per 100 pregnancies) by developed
country, for the most recent year available

Country Birth rate Abortion rate Pregnancy rate Abortion ratio
U.S.    54.4          29.2         83.6           34.9
Real #'s 544,000     292,000      836,000      291,764
10 million teen females
http://www.baby-parenting.com/pregnancy/teen_pregnancy_statistics.html

*Calculation is derived as 5,000*33,300=166,500,000
*see census data
http://www.census.gov/cgi-bin/ipc/idbpyrs.pl?cty=US&out=s&ymax=250a

People who are using two forms of birth control are presumably very wary
 of getting pregnant, and are likely to be taking more care with both
forms of control than would typical people using just one form.

This is a form of self selection bias.

Sylvia.

This argument would only make sense to people with low IQ's, it seems to me.

If you believe that abortion is murder, then the above statements becomes,
"By not promoting murder, you're choosing unplanned pregnancies."

Those who are against abortion believe it to be murder, so this argument
will convince no one.