Chris Davies wrote:

This gave rise to "Spider-girl".  She leapt around in her dad's old uniform
(and, true to all comic book standards, filled it out lusciously).  She had
all the powers and everything.

One might argue that the spider bite altered Peter's DNA (a. la.  "The
Fly").  This is supported by the old, old comics where Peter at one point
grows four additional arms.

        It's also supported by the fact that the children of at least one
other "altered human" (actually, a couple of altered humans) in the Marvel
Universe have been mutants.

        Namely, Reed and Susan Richards, of the Fantastic Four.

>From a strictly clinical standpoint, ionizing radiation has virtually no
chance of producing a consistant modification of a person's DNA,
especially in the production of sex cells such as ovum and sperm. Damage
caused by ionizing radiation (be it high energy photons such as gamma or
x-rays; or particles such as high energy free electrons, helium nuclei,
or neutrons) is random and affects the nuclei of cells differently. Any
dose of radiation that could produce such a widespread, consistant,
somatic effect would likely kill or sterilize the subject. Fact is, if
we were so malleable to the effects of radiation, evolution would work a
helluva lot faster than it does. (The average human being is dosed with
about 80-120 millirem (mrem) of ionizing radiation every year of his
life, most of it from the sun and other cosmic sources.)

>From a comic book standpoint, if a massive acute dose of gamma rays can
turn Bruce Banner into the Incredible Hulk, it's no stretch to say that
the somatic effects of an irradiated spider can also modify Peter
Parker's sex cell generating tissues and thus pass on his "spider"
genetic legacy to his children.

Jamie (former nuclear power tech)
-- 
  _____________________________________________________________________
 /---------------------------------------------------------------------\
|---------------J. Austin Wilde and Bridget Ellen Engman---------------|
|----------------------------------------------------------------------|
| Super Critical Reactor Axe Man.    | Proofreader, Fission Park Press.|
| Head Ranger, Fission Park Press.   | "Helen Keller is alive and well,|
| Hired-Gun, P-P-P-Chan Productions. |  and driving in Tucson..."      |
| "If you cooperate, we'll reduce the|    -Printed on a bumper-sticker.|
|  charges from Hit-and-Run Murder   | "'Motorcycle Cop' is a sweet    |
|  to Littering..." -Lord Barons     |  nothing?"         -Miss Piggy  |
 \_____________________________________________________________________/