Son turned 18 and made a little money

[takeda]

My son turned 18 in 2017 and he made just under $4000. I claimed him as a dependent on our joint return. His <4000 came to him on a 1099MISC since he is contracting for an engineering company. Does he need to file taxes? If he does, then he needs to pay Social Security and Medicare as Self-Employment tax. I am unclear what to do here.

Thanks,
Takeda

[linear]

As he had self-employment income of >$400, he is required to file (and will have to pay self-employment tax).