DNA is a chain of chemical nucleotides consisting of 4 bases: adenine (A), thymine (T), cytosine (C), and guanine (G) [1].
In the human genome there are about 3 billion bases.
Since there are 4 possibilities for a given base, then each base can be represented by 2 bits (say 00=A, 01=T, 10=C, 11=G).
So, there are approximately (3billion x 2bits)/2^30 ~ 5.6gigabits of information in the entire human genome.
Now, half of an individual's genome comes from his biological father and another half from his mother.
Therefore, during the intercourse 2.8gigabits of information is transmitted.
Averaged across ages 15-44 an intercourse lasts for roughly 20min (very optimistically) [2].
Thus, the average information transmission bandwidth is about:
(2.8gigabits x 1byte/8bits)/(20min x 60sec/min) ~ 306 Kbytes/sec

In comparison, my Cox Communication internet speed is about 1243.5 Kbytes/sec (almost 4 times faster or equivalent to the transmission speed of a 5 minutes long intercourse) [3]. This is an interesting case of human intelligence equating/beating nature in efficiency!

[1]http://en.wikipedia.org/wiki/Deoxyribonucleic_acid
[2]http://answers.yahoo.com/question/?qid=1006042220265
[3]http://reviews.cnet.com/7004-7254_7-0.html