I have heard many different opions on this... I have heard that she can because the blood flow will wash out all of the sperm and other people tell me that that is when she is close to beeing most fertile.. I just don't know??
Can a girl get knocked up on her period?
yes it is possible
When pigs mate, is it called Shake 'n' Bacon? or Porking the other white meat?
She's least fertile at this time because it's some time before and after ovulation, but it's not completely reliable as a contraception method.
The period happens because the egg was not fertilized and implated into the uterine walls. The period is a breakdown of the uterine walls and is flushed out. At this point there is(should not) be any egg to fertilize. So impregnating a female while she is on her period is highly unlikely.
The problem is that sperm can live up to 5-7 days in the vagina. If you have sex towards the end of her period and then she were to ovulate very early, well then you could run into a problem.