Maybe that's why married couples start to look alike :)

  _my_ DNA will be floating throughout my wife's body

Strictly speaking, only copies of half of your DNA.

Each time is half, but it's not always the same half. I think it's a 50/50 chance each time, so after 2 it's about 75%, 3 is about 88%, etc.

I don't think they're claiming that this stuff sticks around in any significant quantity after the fetus is delivered.

Animal studies have suggested fetal stem cells can take up permanent residence in the mother, so it's possible. See:

http://www.vetscite.org/publish/items/002393/index.html

(...which is someone's cut & paste of http://www.newscientist.com/article/mg18725134.300)

funthree said By the time a mother has had a few kids, her blood has held all of the DNA in the family. and that's mostly true :-)

Yes, agreed.