Alice and Bob, both unmarried adults, engage in consensual intercourse. Alice lies to Bob about her use of contraception or sabotages Bob's use of contraception, and as a result, Alice becomes pregnant.

Alternatively, Bob and Alice, both unmarried adults, engage in consensual intercourse. Bob lies to Alice about his use of contraception or sabotages Alice's use of contraception, and as a result, Alice becomes pregnant.

In either case, could there be any criminal or civil liability? I'm not talking about child support or any custody issues.

Any jurisdiction.

  • 4
    This is in part very jusrisdiction dependant - in some countries there is no way for Bob around being needed to pay child support, in other countries the manipulating party has just turned his consensual intercourse into rape.
    – Trish
    Dec 15, 2022 at 15:00
  • 3
    @Trish Whether this is rape or assault or anything similar is exactly what I'm interested in. Any jurisdiction that you're familiar with.
    – Ron Trunk
    Dec 15, 2022 at 15:06
  • 3
    Child support is usually a payment to the child, and you pay because you are the father or mother. Wanting or not wanting to be a parent may not matter.
    – gnasher729
    Dec 15, 2022 at 18:26
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    @gnasher729 Right. I was specifically not asking about child support.
    – Ron Trunk
    Dec 15, 2022 at 19:30
  • 3
    I remember precedent about a related question: Bob had AIDS, and knew it, but had sex with Alice without telling her. Alice caught AIDS. Criminal charges were successfully pressed against Bob.
    – Stef
    Dec 16, 2022 at 9:48

4 Answers 4


These acts could be sexual assault. Pregnancy is irrelevant to the analysis.

Deviating from the sexual activity consented to

A majority of the Supreme Court of Canada, in R. v. Kirkpatrick, 2022 SCC 33, in the context of a sexual assault charge, held that where birth control measures "change the physical act itself, like condom use" they are part of the "sexual activity in question" that is being consented to. Deviation from that activity is stepping outside of the consent.

For the majority, birth control measures can very well change the physical act and can be a condition of a complainant's consent. In Kirkpatrick the issue was condom use, but the language the majority used was "birth control measures." Whether birth control measures are in fact alter the physical act to which consent is granted in particular circumstances depends on the facts of the scenario. See para. 100.

What matters is whether the method of birth control changes the physical nature of the act (not whether the purpose was to prevent pregnancy) and whether consent was conditioned on that. So methods like diaphragms, condoms (penile and vaginal variants), and other barrier methods are all probably relevant.

Consent vitiated by fraud

There is an alternate path to sexual assault: if the consent was vitiated by "deceptions about the conditions or qualities of the physical act." See R. v. Hutchinson, 2014 SCC 19. Deceptions that deprive a person from the choice not to become pregnant, or exposing a person to an increased risk of becoming pregnant, or exposing a person to a significant risk of bodily harm such as a risk of contracting sexually transmitted diseases can all vitiate consent.

This path to sexual assault is not as straightforward as the path described above from Kirkpatrick, as it requires a showing of dishonesty, which can include non‑disclosure of important facts, and a risk of serious bodily harm (R. v. Cuerrier, [1998] 2 S.C.R. 371).

At least one court has said this reasoning does not apply when a person falsely represents that they are taking a birth control pill and then gets pregnant (PP v. DD, 2017 ONCA 180). This was in the context of a civil claim for sexual battery, but the court considered the reasoning from Cuerrier and found it was not analogous because the deceit had "no physically injurious consequences" for the plaintiff. The court recognized the consequences of a person having to support a child, but in the context of a wrong based on physical contact, what matters is physical damage.

the appellant's alleged damage is principally emotional harm or, in other words, hurt feelings and lost aspirations and/or career opportunities flowing from the birth of his child. His situation, as a man, is quite different from that of the woman. Clearly, there are profound physical and psychological effects on a mother undergoing a pregnancy that do not apply to the father of the child. The appellant was not exposed to any serious transmissible disease or other significant risk of serious bodily harm flowing from the intercourse. Moreover, it is noteworthy that the appellant was willing to assume some risk, albeit small, that pregnancy would result from the several instances of sexual intercourse, a risk present even where the woman is taking contraceptive pills.

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    I'd note that it seems like the court ruled in a one-sided manner: not using a condom would be sexual assault but not using birth control would not be. Dec 15, 2022 at 22:57
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    Since the ruling in Kirkpatrick concerns "birth control methods", would this ruling not apply to deception about the use of a condom as protection against STDs, in circumstances where pregnancy is not a possible outcome (e.g. between gay men)? Or is the term "birth control measures" here meant in a more general sense that includes condoms even when not used for contraceptive purposes?
    – kaya3
    Dec 15, 2022 at 23:47
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    @JonathanReez I believe there is a huge difference between the two: condoms not only prevent pregnancies but they also prevent STDs. So not using it adds a huge number of possible negative consequences to the sexual act. Birthcontrol does only that. So the point here is that if you decided to have sex with a protection against STDs, removing it does change the risk-assessment of the act. Pregnancy is a natural part of having sex and arguably isn't really a risk (except for woman in certain cases).
    – Bakuriu
    Dec 16, 2022 at 7:05
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    @Bakuriu The idea that the consequences of a control system failing shouldn't be considered a risk because it was likely to happen anyways without the control system in place is just nonsensical.
    – Chuu
    Dec 16, 2022 at 22:34

In either case, could there be any criminal or civil liability?


Not in any U.S. jurisdiction of which I am aware. One or two states (including California) have recently considered passing laws to that effect, but to the best of my knowledge they have not done so.

The answer to this question from user48216 provides a good law journal reference to support this assertion.

  • 2
    @MichaelHall U.S. law doesn't really recognize the concept of conditional consent to sexual activity. It is an all or nothing affair at any given moment. One can terminate consent at a moment in time in most states, but that is a different concept.
    – ohwilleke
    Dec 15, 2022 at 20:21
  • @MichaelHall "post-action withdrawal of consent" Absolutely not. Definitely no such thing is recognized in American law.
    – ohwilleke
    Dec 15, 2022 at 22:05
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    @MichaelHall "Could a man claim coercion based on the lie?" Not under U.S. law. The linked article is not based upon a legal standard, it is based upon aspirational moral standards (and possibly institutional policy standards). Its analysis is not consistent with the prevailing legal standards in the U.S.
    – ohwilleke
    Dec 15, 2022 at 23:26
  • @MichaelHall It does not matter if you "flip the script" in the manner indicated under existing U.S. law.
    – ohwilleke
    Dec 15, 2022 at 23:36
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    @MichaelHall "Could the decision to enter into a sexual relationship be viewed as a "contract" of any sort?" Modern U.S. law does not view it that way. This was the historical justification for the exemption from criminal liability for marital rape but that no longer exists in all or almost all U.S. jurisdictions. It was also a theory relevant to the heart balm torts that have mostly been abolished in the U.S. (and have been abolished in all U.S. jurisdictions in the manner relevant here). Islamic law has contractual marriage concepts (e.g. "temporary" marriage) related to consent to sex.
    – ohwilleke
    Dec 16, 2022 at 0:00

In the United States, there apparently is neither criminal nor civil liability in such circumstances.

Cases of sexual deceit resulting in an unwanted pregnancy have not received sympathetic treatment in the courtrooms. While New Mexico has no earlier cases on point, several other states have addressed this issue and have unanimously rejected these claims. Those rulings involving individuals who fraudulently or negligently misrepresent whether the individual is using birth control are premised on two overriding policy concerns.

"Tort Law: Tort Liability When Fraudulent Misrepresentation Regarding Birth Control Results in the Birth of a Healthy Child - Wallis v. Smith", Brenda Saiz, New Mexico Law Review Volume 32, Issue 3, Summer 2002 (page 550)

The first concern Saiz describes is that allowing such claims is not considered in the benefit of the child. The second concern is that of privacy.

  • 2
    Excellent reference. Your answer is better supported than mine.
    – ohwilleke
    Dec 16, 2022 at 20:07

Generally the issue involves two related deceptions, and (to answer the question) legal culpability in both cases depends on the jurisdiction:

(1) to what extent did either party trick the other into parenthood (however this is achieved should not matter), and/or

(2) to what extend did either party inflict risk of sexually transmitted disease on the other.

In the first case, at least prior implied consent would need to be established as to the desirability of the potential consequence (i.e. pregnancy); in the second case, it would need to be established that prior dismissal was expressed that measures to prevent disease transmissions were explicitly not of concern.

  • Where is this the law? Do you have any references or legal authorities to support this claim?
    – ohwilleke
    Dec 16, 2022 at 20:08

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