There are no laws concerning children and front seats. There is a law about children and the use of child safety seats.
No special law exists to children riding in the front seat. Texas requires all children under 8 years of age or under 4'9" to ride in child safety seats. Texas law requires front seat occupants drivers and passengers to be in seat belts.
not allowed
you must spit on their head and shove it out the window
12
In Maine, children under 12 years old are required to ride in the back seat of a vehicle when it is practical to do so. Children can only ride in the front seat if all back seats are occupied by other passengers under 12 years old or if the vehicle does not have a back seat.
40 lbs.
I found a really helpful PDF put out by the Utah Safety council. According to it, there is no law regarding children riding in the front seat of the car: http://www.utahsafetycouncil.org/assets/pdf/utboosterlaw.pdf It is recommended that children under age 12 ride in the back seat, or to turn the airbags off if a child under 12 is in the front seat, but there is no law saying you have to.
Children under the age of 8 must be properly secured in an appropriate child restraint system in the back seat of the vehicle. It is recommended that all children under the age of 13 ride in the back seat for optimal safety.
Children under 12-years of age must be restrained in the back seat of a car in the State of Texas.
You may not ride in the front seat of a car till you are 13 or older and must be over 85 pounds but this does not apply to cars without a back seat.
The law varies by location, but in general, it is recommended that children under a certain age and size (typically around 12 years old and under a certain height) should not ride in the front seat of a car due to safety concerns with airbags. It is important to check the specific regulations in your state or country regarding child passenger safety.
In the US, under current law, this is probably illegal in every state, though I'm not positive about that. The usual cutoff age for riding in the front seat is 12.