That's what the kids are craving too. Mommy & Daddy make them feel safe when they are insecure. Why is it so taboo to alow small children the security that their parents will protect them why the sleep. Think about it really, we force them to sleep alone when in reality less than 1/2 their life is it really "inappropriate" to sleep (NOTHING SEXUAL) with another human. Out of an 80 year life span apox 16-18 years they have to sleep alone, why are we forcing young children to be independent sleepers when technically it's not an adult skill either. Eventually your child will want their own space, why ignore their need for your comfort when young.
TO CLARIFY: Not newborns, simply because I am not here to argue safety lets start this at age 10 months. Also no sexy time talk, I highly doubt every moment you lie next to your SO you are sexually explicit, 98% of the time you are sleeping.