It's not that it won't win you friends, it's the fact that this is factually untrue.
1) Teenage pregnancy rates have been falling over the last 15 years. Turns out that education and decent sex ed and family planning goes a long way in tackling teenage pregnancy.
2) The idea that people previously didn't use to have families because they couldn't afford them is again, factually untrue. Wildly so. Not sure where you get that idea from, but people have been having more children than they can 'afford' since time began. Its just that previously, child mortality rates were much higher or we were happier to stand by and let kids be raised in poverty (which is a dreadful idea in the long run as I'm sure you can imagine).
3) the Tories were in power for the majority of the 90s. Labour only took over in 1997, and they continued the overall tory spending plans for the first two years of their administration.
I'm afraid everything you have posted is basically the same tired anecdotal stuff that has been proven false repeatedly, often in this thread. It's the stuff the daily mail puts on their front page every so often, about families who are out of work and having children to live off YOUR taxes. Unfortunately, that's simply not the case usually. The number of families doing this is tiny.
If you actually wanted to cut welfare, you need to cut welfare to the biggest group of welfare recipients - pensioners. 46% of the welfare bill goes on the state pension, whereas Jobseeker's Allowance is only 3% of the bill. Even if you add in housing benefit, income support, council tax benefit and Jobseeker's allowance together that's still only 25% of the welfare bill, and the number of people on those benefits that you describe is *tiny*.