Not by itself, no. Power forms separately from the reproductive process. Patriarchal societies don't develop just because men can briefly control their part in the human reproductive process. They develop because the party that is most removed from the workforce during a pregnancy contributes less to the workforce and therefore has less power for the duration - then repeat that over an entire society.
But under those conditions? It's not a stretch, for example, to imagine a society emerge under those conditions where fertile women of a childbearing age are treated with ridiculous care - to the point of being removed from the world. A family with the position and finances to pamper their childbearer(s) would probably also have a high position in that society, right? But part of pampering their women means that they can't really be exposed to decision-making, as that is stressful.
Conversely, a childbearer in a family without status or funds to ensure a well-born child would have at least the opportunity to be part of decision-making... but why should they be allowed when the ruling class doesn't do so?
So I think it would ultimately end up as a society that puts its prize childbearers on a pedestal, as an ideal to live up to, without really allowing for the fact that hardly anyone can actually live up to it.
Would women have extra rights or privileges in this society? Probably not, because the "ideal" woman is a prize childbearer: someone who bears good children (the ideal process of which completely removes them from activity). During pregnancy at least, there wouldn't even be a point to them having basic human rights so much as strict legal protections - you can beat your wife only when they aren't pregnant, so the wife has to chose between relative peace during pregnancy or abuse.
Worst-case, you'd get a system of Eugenics
resembling what you see in animal husbandry.
It would ultimately be a question of what your society valued. So long as the women of this society are primarily valued for their procreative abilities, then it's likely not going to be significantly different from real societies where that's the case. Its just that in your society, their happiness would be of paramount concern, so what you might get is women treated as pampered, highly-indulged commodities.
I agree with Deus Denuo. It may increase the control of a certain aspect of their lives, but not to the point of matriarchy. To get to that point, women would also need a biological deterrent that would make rape more difficult, and both sexes would need a change in hormones that would make women more aggressive than men.
edited 26th Feb '17 7:46:55 PM by shiro_okami
It really does come down to workforce issues. In a pre-industrial society you need mothers cranking out children as fast as possible since about half of them would die before adulthood. You also can't exactly force a woman to work throughout pregnancy, just carrying a child to term is a massive biological strain.
Red Spade, Black Heart
The first thing that popped into my head is that female armadillos have that exact ability. They can choose to become pregnant or not. They can also store the male's sperm and use it whenever they want. If you're doing this idea, consider making the characters armadillos. 
Or make them like cuttlefish, in which the male stores his sperm in one of his tentacles, then detaches it and gives it to the female, who then uses it to fertilize her eggs at some time of her choosing.
As far as I can tell, patriarchy inevitably develops with agriculture and the accumulation of property. If a woman is her husband's property (which, to a greater or lesser extent, describes much of human history), her control over her own fertility will be subject to his will. So no.
The degree of patriarchy varies, of course, but it's still nearly universal in some form. Even the Iroquois were led by men, though women chose the leaders.
It may be possible that in areas where women had legally independent rights (Celts and Norse), they might be able to parley their power into something like the Iroquois system (I don't see systematic female rulership at any point in time where leaders are expected to be warriors). On the other hand, I certainly don't see China becoming matriarchal through this system, because "Woman's greatest duty is to produce a son" will lead to the opposite result to what you're looking for.
Depends on how you define "control" from the sound of it perhaps contemptuously easy would be the way to go.
Perhaps different anatomy such as not going through the pelvic bone or some such.
On making a matriarchial society if women can control their reproductive processes, would voluntarily modifying women to have male reproductive organs while keeping theirs work?
A couple of generations and many failed BS 'Bathroom Bills' down the line? Maybe.
I once read a femminist internet article titled "the myth of the magical women" or something, basically it said that women are only property of men so then can be sure that the child they're bearing is theirs, to secure offpring, since in the past it was said that the only way to secure afterlife was with your childre making rites for you when you died.
But that article presents the case that, in the past, men didn't know anything about the role they played in reproduction, and thought that women could have children whenever they wanted without their help, so they were venerated as magical and were the ones in charge.
I really think thats very unlike in real life, but in the case OP describes it could be a possibility, what do you think?
Tho, I think you can do the same without denying men that knoweledge, but you would still need to make society evolve different than it did in real life, without people caring which child belongs to who, so without families, without enheritance and the children being cared by everyone, not just their parents. Like scientist think itused to be in the past,no like a pack of animals, because with the animals women are like possessions of the alpha male, aren't they? I dunno, don't know much about animals.
Virile Member
I think it's preposterous. People were never so ignorant as to believe women are capable of parthenogenesis.
"Let him that hath understanding count the number of the beast, for it is the number of a man; and his number is 0x29a."
. In this worldbuilding scenario, pregnancy would be an active rather than passive process. A woman could biologically determine the sex of their child in the womb and make it a boy or girl. They could choose whether to carry it to term or abort it completely. Rate of gestation could be controlled, sped up or slowed down as needed. Birth would be a painless or maybe even enjoyable experience. Exteme stress would be detrimental to the pregnancy, and the baby''s health could be adversely affected or cause it's death. would these advantages be enough to justify or lead to a matriarchal society?