during a sex scene (female rear nudity) is seen

Several graphic sex scenes throughout the series.

Strong bloody violence throughout, some of which is directed at children, generally very disturbing.

A baby is rolled into traffic and hit by a car. Very shocking and disturbing.

Skinned and gutted bodies shown in graphic detail.

A man is killed by a high frequency sound wave which fries his brain. Highly violent and disturbing as blood pours from his nose and mouth as he screams.

Bloody shootings and stabbings in pretty much every episode.

Violence towards humans and aliens throughout the series.

Each episode contains some moderate to strong amounts of violence.

Violence is bloody in several episodes.

Strong language is used casually, but not pervasive. In the first series there's 28 uses of the word "fuck," as well as casual profanities. In the second series there's one use of "fuck." The third series has no F-bombs, but still other casual profanities. In the fourth series there's one use of "fuck" in the finale.

A few scenes in bars some contain fights characters are seen drinking alcohol

An alien takes cocaine.

Alcohol is consumed in a few episodes but hard illegal drugs are referenced but never used and if they are it isn't advertising them.

The most frequent 'drug use' would be when characters are given a drug called 'Retcon'. There are a few different classes of it but never specified how many or what they do but the drug is to wipe the memory of the person who takes it. It's mostly slipped into drinks. It is mentioned in an episode of the first series that a character gave a man the Retcon drug every month for two years.

A man on death row is to be executed by injection, but something goes wrong and he is seen convulsing on the table. This scene can be frightening.

Before dying, a man screams that he is coming for a little girl he assaulted murdered and that she better run. This scene is disturbing.

Graphic murder of children shown in several episodes, very disturbing.

(Deleted. Personal opinions about suitable viewing ages are not appropriate for the Parents Guide.)

Some episodes do not end on a happy note and there are many occasions where the victory of the protagonists feel hollow and meaningless compared to the losses they have suffered.

Children are used by an alien as recreational drugs, a mutated child is shown to be the product of this. Incredibly disturbing, especially considering the children are conscious and sentient during this process.

A woman is forced to watch her son be graphically murdered.

Each episode is intense and emotional in it's own ways.

One episode contains cannibals and it is strongly implied they killed and ate a small village. When questioned why they did this, they answered because they wanted to. This answer horrifies a main character.

One character is immortal (although most viewers should already know) and he is shown to be killed in some mild to strong manners. In the episode "Immortal Sins" of Season 4 there is a flashback of the characters life before the series. As people realise he is immortal and they repeatedly kill him for torture and entertainment. We hear gruesome sounds but don't see much except for bloody marks on his body.

Each series has gotten more mature, Children of Earth is more intense than the first two series put together and Miracle Day is quite shocking in some parts.