It could be a warning against AIDS!!!!!!!

Or it could be that Henry is an alien, sent to earth to spawn a child, which becomes a mutant because of incompatible genes. The worm he gets through the mail is code for death. He has been ordered to kill the child. But now he is too fond of it! He checks the mail box in case they change their mind about killing the child. They do not. They send a message through the worm he has received that the baby will become dangerous when bigger. But by now Henry is so wrapped up in his human guise that he has forgotten that he ever was alien. The fat faced woman is his lost memory of this fact. She steps on the semen to remind him to kill the child. That's why the man in the planet's face replaces fat cheeked woman's face for a second. Henry kills the kid, by accident, but it is too late. The child becomes something else: energy. hence sparks. The energy becomes everything, even the film itself. It travels back in time and we see moments of it appearing in the form of the chicken bleeding and sparks.

What the pools of round water mean, I don't know. They appear many times. Maybe Lynch saw RING OF BRIGHT WATER. Maybe the baby is an otter.:)))

The film could be a psychic warning about AIDS!!!!!!!!!!!!!!!!!!!!! too. 

"Harry, I'm going to let you in on a little secret. Every day, once a day, give yourself a present. Don't plan it, don't wait for it, just let it happen. Could be a new shirt at the men's store, a catnap in your office chair, or two cups of good, hot, black coffee. Like this."  -Dale Cooper

"What? Did your life pass before your eyes? Cuppa tea, cuppa tea, almost got shagged, cuppa tea..."

"Harry, I'm going to let you in on a little secret. Every day, once a day, give yourself a present. Don't plan it, don't wait for it, just let it happen. Could be a new shirt at the men's store, a catnap in your office chair, or two cups of good, hot, black coffee. Like this."  -Dale Cooper

Sure, it's about Hitler. All the themes are there. The baby is a shaven jew. It's pillow is even striped like their pajamas. The radiators are the gas chambers and crematoriums. The pencils march like nazi soldiers in the eraser machine. The nuke explosion picture on the wall symbolises the end of the war. The industrial landscape is Germany and how it felt.

It is also about Satan, but I'll leave that for him to detail. 

Silly rabbit.

 Eraserhead was CLEARLY an advertisement for the Ticonderoga pencil company