A Baby who has eitehr No Father or possibly No mother... Often the result of A Condom Catastrophe!
Amy: Your baby is so cute!

Vicky: Thanks she is my Condom catastrophe, bastard baby!
by Forever Fun 'N' Faithful August 30, 2009
When a female has her period down a drain, such as a shower drain, and then a male ejaculates into the same drain, The egg from the female is fertilized and from that egg forms a Mutant Bastard Period Baby. In order for fertilization to occur in separate drains the temperature MUST remain in between 88-97 degrees fahrenheit and the sperm and egg must meet in a nutrient rich environment within the sewer system. Also Known As: MBPB's. These MBPB's have been thriving in the drains and sewers of major cities for many years. In third world countries they accumulate in swamps and poorly irrigated marshes. Many MBPB's have a distinct order, usually an asparagus or unclean gouche. They have 7-28 fingers and 1-13 eyes depending on their age. Ginger MBPB's, which are fertilized by either a Ginger sperm or Ginger egg have received the recessive gene making them twice as nasty. The only clean way to eradicate an MBPB is to use any type of window cleaner or an ultra-violet flashlight.
"I have jacked it so much down the drain that I have to be the father of so many Mutant Bastard Period Babies"

"Jesus you smell so bad! Did you fuck an MBPB?"
by John Patrick B May 14, 2008
A Chubby Bastard Baby is when the baby that has just been born and is very fat.
Wife: OMG babe look at how beautiful our baby is!

Husband: Fuckin hell that’s a Chubby Bastard Baby, I’m outa here.
by ChunkyChestnut February 9, 2022